s 



LIBRARY OF CONGRESS, 



Shelf ...HA* 



UNITED STATES OF AMERICA. 



V 



INTRODUCTION 

TO 

ELEMENTARY PRACTICAL 

BIOLOGY 



H Xaborators 6utt>e 

tor 

UMab^Scfcool anD College Students 



BY / 

CHARLES WRIGHT DODGE, M.S. 

PROFESSOR OF BIOLOGY IN THE UNIVERSITY OF ROCHESTER 





NEW YORK 

HARPER & BROTHERS PUBLISHERS 

1894 



3 ^ i r -£. 



Copyright, 1894, by Harper & Brothers. 



All rights reserved. 



^ 



nature, not books.''' 1 — Agassiz 

" Real knowledge in science means a personal acquaintance with the facts, be 
they few or many.' 1 '' — Huxley 

" TJie ideal of scientific teaching is, no doubt, a system by which the scholar sees 
every fact for himself and the teacher supplies only the explanations." — Huxley 



PREFACE 



Students, particularly those of the natural sciences, 
are no longer satisfied to receive didactic instruction, 
but want the training which will fit them for investi- 
gation. In Biology it is the custom to furnish such 
training by having the student verify the facts acquired 
by professional investigators. The methods of teach- 
ing now in vogue for elementary classes are methods of 
instruction rather than of education. The student gets 
the most of his knowledge from books or from lectures, 
and very little from specimens. When thrown upon his 
own resources, as when called upon to examine some 
natural object and to describe it in his own language, 
he is entirely powerless. If he can find in some book a 
description of the object, he may, perhaps, be able to 
verify it, and, using that in the book as a pattern, to 
write a description of his own. 

A method of teaching which consists solely of the 
verification of the printed statements often leads stu- 
dents into temptation, for there are always a few who 
have too little mental strength and moral courage to 
resist using as their own the facts given in books, par- 
ticularly when it comes to dissecting a difficult organ 
or to tracing a minute duct. Not a few students who 



VI PEEFACE 

have been taught by the "verification method" have 
confessed committing to memory the detailed descrip- 
tions of their specimens in preference to doing the 
work necessitated by a practical examination. It is 
needless to say that with such students laboratory 
work fails completely to accomplish its fourfold ob- 
ject — viz., to teach the student, first, to observe cor- 
rectly; second, to distinguish essential from non-essen- 
tial facts ; third, to draw proper conclusions from the 
facts observed ; and fourth, to express in writing and 
by means of drawings the results obtained. 

For the purpose of developing in the student the 
power of independent observation, to teach him that 
the source of all knowledge is not "the book" rather 
than the specimen, that there is a great deal to be seen 
besides that which "the book" describes, and that he 
is not to consider that, though his observations may 
not agree with those of "the book," the latter must, 
necessarily, be right — these are the reasons why this 
guide has been written. 

The guide consists essentially of questions on the 
gross and minute structure and on the physiology of a 
series of common animals and plants which are typical 
of their kind — questions which can be answered only 
by actual examination of the specimen or by perform- 
ance of the experiment. Directions are given for the 
collection of specimens, for their preservation, and for 
preparing them for examination, also for performing 
simple physiological experiments. Particular species 
are not required, as the questions usually apply equally 
well to several related forms. 



PKEFACE Vll 

The material of which the guide is composed has been 
gradually accumulated during an experience of nearly 
seven years of teaching high-school and college classes, 
consisting of students of both sexes and of ages vary- 
ing from fourteen to fifty years. With the exception 
of a few additions made while preparing the manual for 
printing, all of the work herein detailed has been per- 
formed by college students, and a very large part by 
students in the second year of their high-school course. 

Although it is thought that the topics are so arranged 
and the questions so worded that any one of average 
intelligence can study any or all of the organisms given, 
still it is not intended that the guide shall supersede 
the instructor, but, rather, aid him. The student will 
always require the advice and suggestions of his teach- 
er, who will need to point out many of the structures 
which here are only named, and which it would be im- 
possible to describe so that the student could find them 
for himself, without defeating the very object which the 
guide seeks to attain. 

As this manual has to do entirely with the work of 
the laboratory, it is suggested to those teachers who 
wish to use a text-book also, that nothing better can be 
found than Parker's admirable work, " Lessons in Ele- 
mentary Biology," 2d ed., New York, 1893. 

Following the classification given in the " Text-Book 
of Zoology" of Glaus and Sedgwick, and the "Outlines 
of Classification and of Special Morphology of Plants " 
of Goebel, an attempt has been made to arrange in log- 
ical sequence the organisms to be studied, proceeding 
from the simple to the more complicated. It is desira- 



Vlll PREFACE 

ble that they should be studied in this order. Experi- 
ence has shown that this method can be pursued with lit- 
tle or no difficulty and to the greatest advantage. It is 
very frequently the case, as here, that the simplest form 
is not necessarily the best known. Every one is more 
familiar — by sight, at least — with the frog than with 
the amoeba. The structure of the former resembles that 
of the human body far more than does that of the lat- 
ter. But how many students have even the most gen- 
eral knowledge of human anatomy ? They know, to be 
sure, that the body contains a heart, lungs, stomach, 
etc., but in the great majority of cases would fail to 
locate or, if shown them, even to recognize these or- 
gans. Again, how many students, if called upon to do 
so, could tell more about the frog than that it usually 
lives in the water, is greenish in color, has four legs, a 
mouth, etc., and can jump and swim ? Whether or not 
the frog has a tail is usually a question for discussion. 
As a matter of fact, beginning students have no more 
real knowledge of the higher than of the lower forms. 

That the student is unaccustomed to the use of the 
microscope is often urged as a reason against beginning 
with minute organisms. Does his study of the gross 
anatomy of a rabbit or of a frog teach him anything 
about the manipulation of this instrument ? Sooner or 
later he will have to learn to use it, and it matters little 
when he does so ; the instrument will be unfamiliar to 
him until he actually handles it and learns its use by 
degrees. He should approach it by way of the magni- 
fying glass, and use the low before attempting the high 
powers. In two hours the average student can learn 



PREFACE IX 

sufficient of manipulation to warrant trusting him with 
a microscope. His power of observation will be devel- 
oped only by training. It is advisable to begin with 
the lower forms, not only because of their simplicity of 
structure, but also because of the value of this method 
in tracing the development both morphologically and 
physiologically of the tissues and organs of the higher 
organisms and the evolution of forms. Though this 
plan seems preferable, it is not absolutely necessary 
that it should be followed. The student may begin 
with the highest form and work downward ; or he 
may commence with an intermediate form and work 
either way ; again, he may begin with an intermediate 
form, then go to the lowest and work upward. On ac- 
count of lack of instruments, it may be necessary to 
omit all of the minute organisms and all of the micro- 
scopic work on the higher forms. It is thought that 
the guide can readily be adapted to any of these meth- 
ods. The end to be attained is not to examine as many 
specimens as possible, but to examine them as thor- 
oughly as possible. 

It has been found that the question stimulates the 
student to a degree of mental endeavor far beyond that 
attained by the attempt to verify a printed statement. 
A few of the questions are suggestive rather than capa- 
ble of a definite answer, but these will be found to have 
their use. The notes made in the laboratory should 
form the basis of the recitation, and many of the top- 
ics should be further elaborated and discussed by the 
teacher. 

]\Iuch of the pleasure and instruction to be derived 



X PREFACE 

from the examination of living organisms is lost be- 
cause few people know how and what to observe. To 
most individuals the study of Natural History means 
nothing more than the memorizing of Latin names, of 
long descriptions consisting of unfamiliar terms, of 
" collecting " various kinds of disagreeable creatures, 
and preserving them dried or in alcohol, etc., etc. 

Should this guide, even in the slightest degree, prove 
instrumental in doing away with such a belief and in 
cultivating a taste for the study of nature, then will it 
have accomplished its purpose. 

In one of the appendices is given, under its appropri- 
ate heading, a list of literature which the student may 
profitably consult after having finished the study of 
each organism. In the construction of the guide free 
use has been made of the works named. In another 
appendix is given a brief list of the reagents and some 
of the appliances needed in carrying out the work 
given in the body of the manual. For more detailed 
directions and descriptions the student is referred to 
the works on microscopical technique and laboratory 
methods. 

Acknowledgment is due to Mr. Arthur Willey, of 
Columbia College, who kindly looked over the proof- 
sheets and made a number of valuable suggestions. 

C. W. D. 



CONTENTS 



INTRODUCTION 

Suggestions — Apparatus required by the Student — Dissection — Taking 
Notes — Drawing — Using the Microscope pages xvii.-xxiii 



Part I 

THE BIOLOGY OF THE CELL 

I 
THE ANIMAL CELL, ITS MOEPHOLOGY AND PHYSIOLOGY 

A. — The Unicellular Animals 

Example 1. — The Protozoa: General questions. Example 2. — The Proteus 
Animalcule : Morphology — size, shape, structure ; Physiology — move- 
ments, nutrition, sensation, reproduction ; General questions. Example 
3. — The Slipper Animalcule: Morphology — shape, size, structure; Phys- 
iology — movements, nutrition, nervous properties, reproduction; General 
questions. Example 4. — The Bell Animalcule : Morphology — shape, size, 
structure ; Physiology — movements, nutrition, nervous properties, repro- 
duction ; General questions 3-20 

B. — Cells isolated from the Bodies op Multicellular Animals 

Example 5. — Salivary Cells: Morphology — general structure; Physiology 
— motion, nutrition. Example 6. — Blood Cells: Morphology — red cells, 
colorless cells; Physiology — movements, ingestion, effects of tempera- 
ture. Example 7. — Ciliated Cells : Morphology — general structure ; 
Physiology — movements, ingestion; General questions 21-27 



Xll CONTENTS 

II 
THE PLANT CELL, ITS MORPHOLOGY AND PHYSIOLOGY 

A. — The Unicellular Plants 

Example 1. — Yeast: Morphology — arrangement, shape, size, color, structure, 
iodine test for detecting the presence of starch ; Physiology — effect of 
food-supply upon growth, effect of temperature upon growth, effect of 
light upon growth, nature of the gas given off by the growing yeast, 
formation of alcohol, chemical reaction of fluid yeast, temperature of 
yeast during growth, effect of filtered yeast upon a fermentable fluid, re- 
production ; General questions. Example 2. — Green Slime: Morphology 
— Naked-eye characters — occurrence, color, structure ; Microscopic char- 
acters, Vegetative condition — arrangement, shape, size, color, structure, 
tests for cellulose; Reproductive condition ; General questions. . .28-46 

B. — Cells isolated prom the Bodies of Multicellular Plants 

Example 3. — Spores of Fungi : Morphology — general structure ; Physiology 
— germination ; General questions. Example 4. — Pollen Grains : Mor- 
phology — general structure ; Physiology — germination. Example 5. — 
Water Silk: Morphology — Vegetative condition — Naked-eye characters, 
Microscopical characters — the shape of the filament, the structure of 
the individual filament, the structure of the individual cell ; Reproductive 
condition — general appearance, structure of the fruiting filament, posi- 
tion of the fruiting filament, the conjugating tubes, the zygospores; 
Physiology — formation of starch, effect of light, effect of carbon dioxide, 
growth, cell-formation ; General questions 46-61 



Part II 
THE BIOLOGY OF THE ANIMAL 

SPONGES 

Example 1. — Skeleton of Toilet Sponge: Morphology — shape, size, color, 
elasticity and porosity, structure. Example 2. — Fresh-water Sponge: 
Morphology — shape, size, color, structure ; Physiology — movements, in- 
gestion ; General questions. Examples. — Grantia: Morphology — 
)e, size, color, structure 65-79 



CONTENTS Xlll 

FRESH-WATER POLYP 

Morphology — size, shape, color, structure; Physiology — movements, nutri- 
tion, nervous properties ; Microscopic structure 80-89 

CAMPANULARIAN HYDROID 

Morphology — general form and structure, perisarc, ccenosarc, zooids ; Phys- 
iology — movements, feeding, sensation ; General questions 90-96 

STAEFISH 

Morphology — External anatomy — shape, size, color, structure; the skele- 
ton; Internal anatomy — the digestive system, the reproductive system, 
the water- vascular system, the circulatory system, the respiratory system, 
the nervous system ; Physiology — movements, nutrition, nervous proper- 
ties, reproduction, regeneration of lost portions of the body, sexual re- 
production, the structure of the sexual cells, preparation of the ovum for 
fertilization, fertilization, the consequences of fertilization 97-121 

EAETHWOEM 

Morphology — External characters — general shape, color, general structure, 
apertures ; Internal anatomy — the digestive system, the circulatory system, 
the nervous system, the excretory system, the reproductive system ; Physi- 
ology — movements, feeding, circulation; General questions. . .122-137 

LOBSTER OR CRAYFISH 

Morphology — External characters — the entire animal, the body proper, the 
abdomen, the cephalothorax, the telson, the appendages, the gill-cham- 
ber, the exoskeleton, the organs of special sense ; Internal anatomy — the 
epidermis, the muscular system, the circulatory system, the digestive sys- 
tem, the excretory system, the reproductive system, the nervous system ; 
Physiology — movements, feeding, breathing, nervous properties; Gen- 
eral questions 188-171 

LOCUST 

Morphology — the body as a whole, the head, the mouth-parts, the thorax, 
the abdomen ; Internal anatomy — the muscles, the viscera, the nervous 
system ; Physiology ; General questions 172-188 



XIV CONTENTS 

MOLLUSC SHELLS 

Example 1. — Fresh-water Mussel: General structure. Example 2. — Pond 
Snail : General structure 189-193 

THE SOFT PARTS OF THE FRESH-WATER MUSSEL 

External anatomy ; Internal anatomy — the digestive system, the circulatory 
system, the nervous system, the excretory system ; The examination of 
transverse sections ; Habits 194-202 

FROG 

Morphology — External anatomy— shape, size, color, general structure; In- 
ternal anatomy — the skeleton, the muscular system, the digestive system, 
the respiratory system, the urino-genital system, the circulatory system, 
the external anatomy of the heart, the veins, the arteries, the internal 
anatomy of the heart, the lymph hearts, the nervous system, general 
structure, the central nervous system, the peripheral nervous system ; 
the eye and the ear; Microscopic anatomy; Physiology — locomotion, 
nutrition, development 203-263 



Part III 
THE BIOLOGY OF THE PLANT 

GREEN FELT 

Morphology — Vegetative condition, Naked-eye characters, Microscopic char- 
acters, Reproductive condition ; General questions 26*7-272 

STONEWORT 

Morphology — Naked-eye characters, Microscopic structure; Physiology — 
growth, movements of protoplasm ; General questions 273-284 

ROCKWEED 

Morphology — Naked-eye characters, Microscopic examination ; Physiology 
— the fertilization of the oosphere; General questions 285-296 



CONTENTS XV 



MOULD 



Morphology — Naked-eye characters, Microscopic characters; Physiology — 
the germination of the conidia ; General questions 297-300 

MUSHROOM 

Morphology — Naked-eye characters, Microscopic structure ; General ques- 
tions 301-307 

LIVERWORT 

Morphology — Naked-eye characters, Microscopic structure; Physiology — 
the fertilization of the oosphere 308-319 

FERN 

Morphology — The Spore-bearing, or Asexual Plant : Naked-eye characters, 
Microscopic structure. The Prothallium or Sexual Generation. Physi- 
ology, the germination of the spore and the development of the pro- 
thallium 320-335 

THE FLOWERING PLANT 

Seeds: Morphology — bean, other seeds, some of the chemical contents of 
dry seeds, microscopic examination of starch and aleurone ; Physiology 
— imbibition and turgescence, germination, geotropism, respiration, tem- 
perature of germinating seeds, some of the chemical contents of germi- 
nating seeds, action of the diastase of malt upon starch, osmosis. Stems : 
Morphology — Naked-eye characters, Microscopic structure ; Physiology 
— movements, direct observation of the ascent of water in the stem. 
Roots. Buds : Morphology — Naked-eye characters, Microscopic charac- 
ters. Leaves: Morphology- — Gross anatomy, Microscopic characters; 
Physiology — transpiration, assimilation, movements. Flowers: Mor- 
phology — Naked-eye characters, Microscopic structure; Physiology — 
fertilization 336-377 



APPENDIX 

List of Reagents, etc , 379-393 

Works of Reference 394-409 

Index and Glossary 41 1-422 



INTRODUCTION 



Every student should have assigned him a definite place 
to work, for whose good order he should be held responsible; 
also a drawer in which to keep his instruments, note-books, 
etc. The drawer ought to be provided with a lock to which 
no one but the student and the instructor has the key. The 
most convenient place for the drawer is in the table at which 
the student sits, as here it is more easily accessible than 
elsewhere. If necessary, a case of drawers may be placed 
at some convenient place in the room. 

The laboratory exercises should be at least two consecu- 
tive hours in length, as so much time is consumed in mak- 
ing the preparations for work and in " cleaning up " after- 
wards that but little can be accomplished in one hour, while 
an exercise which lasts three hours is very likely to fatigue 
the beginning student unduly. 

A certain fee ought to be charged for the use of micro- 
scopes and other apparatus, and for specimens, etc. Some 
wear and tear of instruments is to be expected, but any 
damage beyond this should be made good by the student. 

Economy of material must be practised, but not to such 
an extent as to interfere with obtaining a clear idea of the 
structure of each organism. Each student should provide 
his own specimens of the commoner forms, e. g., earthworm, 
locust, and various plants. Before putting specimens into 
hardening reagents, be sure to see that the body and its ap- 
pendages are properly arranged, otherwise they may stiifen 
in positions awkward for handling. Preserved specimens 
B 



XV111 INTRODUCTION 

of the marine forms may be obtained from the Department 
of Laboratory Supply of the Marine Biological Laboratory 
at Wood's Holl, Mass., or from Ward's Natural History Es- 
tablishment, Rochester, N. Y. 

Whenever possible, the living organism ought to be close- 
ly observed before any work is done on dead specimens. It 
is an excellent plan for the student to have a live specimen 
before him while studying the anatomy of dead material. 

Apparatus required by the Student 

Each student should provide himself with the following : 

1. A medium-size and a small scalpel. 

2. A pair of medium -size and a pair of small (oculist's) 
forceps, both with straight points and rough tips. 

3. A pair of fine curved scissors, which should meet ac- 
curately at the tips. 

4. A pair of dissecting needles, made by fastening the 
eye-end of stout sewing-needles into wooden penholders. 

5. A razor. 

6. Twenty-five slides and a half-ounce of cover-glasses. 

7. Two note-books, one for making condensed notes while 
doing the laboratory work, the other in which to write in 
ink a full and carefully worded account of the observations 
made. 

8. A number of cards of bristol-board cut to the size of a 
large postal-card. Upon these drawings are to be made. If 
desired, a blank-book of thick calendered paper may be used. 

9. A hard pencil, either HHHHH or HHHHHH 
Faber is recommended. 

10. A piece of india-rubber. 

11. An apron, preferably of rubber. 

12. A towel. 

Dissection 

The object of dissection is to separate the various parts 
in such a manner as to display their shape and mutual rela- 



INTRODUCTION XIX 

tions, and it consists almost entirely in the removal of the 
connective tissues which bind the different organs together. 
The student must plainly understand that hacking specimens 
to pieces is not dissection. 

While dissecting, the following rules should be borne in 
mind ; 

1. Fix the specimen in whatever position may be most 
convenient for work. If it be a large object, as, for exam- 
ple, a lobster or frog, lay it dorsal or ventral side uppermost 
as may be desired, and with the head turned away from one. 
If the specimen be so easily moved as to interfere with the 
work, stick pins obliquely through the softer tissues into the 
dissecting- tray or the wax in the bottom of the dissecting-pan. 

2. The tissues of fresh specimens must be moistened from 
time to time with water or with normal salt-solution to pre- 
vent the drying and distortion of parts. Alcoholic material 
should be examined in dishes containing fifty per cent, alco- 
hol. If such specimens be large, e. g., lobster, and it be de- 
sirable to examine them on the dissecting-tray, place them 
for two or three hours previous to the time when wanted in 
a mixture of equal parts of water, alcohol, and glycerine. 
They will then keep moist even in the open air. 

3. Before making a cut in any direction, study the speci- 
men carefully, and note where the cut must be made in or- 
der to expose the part wanted with the least injury to sur- 
rounding parts. Specimens unnecessarily mutilated should 
be replaced at the expense of the student. 

4. In dissecting and cleaning muscles, nerves, and blood- 
vessels, stretch them slightly and work in the direction of 
their length, never crosswise. 

5. Avoid unnecessary handling of the parts, and do not 
pinch them -with the forceps. 

6. Do not allow scraps to accumulate on the specimen. 
Sponge away blood-clots. With a pipette wash away the 
debris which accumulates on specimens dissected under wa- 
ter, or change the water frequently. 



XX INTEODUCTION 

7. Good work cannot be done with dull instruments, 
therefore keep them clean and sharp. 

8. When work is finished for the day, all instruments 
which have been used should be washed, or wiped with a 
damp cloth, to remove all adhering scraps of flesh, thor- 
oughly dried with a soft cloth, then carefully oiled or rubbed 
with vaseline. The joints of the scissors should receive close 
attention. 

It is a good plan to require each student to prepare a 
careful dissection of some animal or system of organs. These 
preparations may be used to form a laboratory museum. 

Taking Notes 

A complete and carefully prepared description must be 
made of every specimen examined. This description will 
consist mainly of answers to the questions given in the 
manual. To these are to be added whatever independent 
observations the student may make. If the answers be 
given in the same order as the questions are asked, it will 
be found that the former constitute a brief essay upon the 
organism examined. 

Two note-books should be used, one in which to write 
hastily in the laboratory the results of the observations 
made ; the other to contain the carefully prepared descrip- 
tions which, written plainly in ink and with due regard to 
rhetorical form and expression, are intended for examina- 
tion by the instructor and for permanent preservation. 
Make the laboratory notes full and complete, record the ob- 
servation as soon as it is made, leave nothing to the mem- 
ory; otherwise the second set of notes will suffer. In an- 
swering such questions as are mainly theoretical, give all 
the reasons you can pro and con. 

Drawing 

Draw every specimen examined and every dissection 
made. Endeavor to get correct outlines and relative posi- 



INTRODUCTION XXI 

tion of parts. Shading is seldom desirable. Draw every- 
thing to scale, and mark on the drawing the scale adopted. 
Always sketch in the outline faintly at first, then fill in the 
details. When the specimen is bilaterally symmetrical, draw 
a faint line to represent the median line, sketch the outline 
of the left, then of the right side, and fill in the details. 
Make every drawing large enough to show all of the parts 
plainly. Name every part or organ in every drawing. It 
adds much to the appearance and value of the drawings if 
they be colored with water-colors, using the dull tints for 
the larger and the bright colors for the small organs. In a 
set of drawings of the same specimen always use one color 
for the same system or organ. Indicate arteries in red, 
veins in blue, and other parts in their natural colors. 
Drawings must not be made too small. 

Using the Microscope 

1. Take the instrument from the case together with the 
eye-piece and objective to be used, then close the case and 
set it aside out of the way. 

2. Examine every part of the instrument to be sure that 
it is clean. Wipe off the dust by brushing lightly with a 
soft clean cloth. 

3. If there be anything but dust on the objective, wipe 
the latter with a soft, moist cloth, then dry immediately 
with a soft cloth. If this fail to remove the dirt, take the 
objective to the instructor. Do not use chamois skin or 
soiled cloths of any kind. A worn linen or silk handker- 
chief, kept perfectly clean and free from dust, is as good as 
anything that can be found to clean the microscope. 

4. Put in the eye-piece ; screw on the objective. 

5. Incline the tube at a convenient angle. 

6. Turn the tube down to about one fourth of an inch 
from the stage. Be exceedingly careful to avoid contact 
of the front lens with the stage or with anything upon 
it. 



XX11 INTRODUCTION 

7. Arrange the mirror so as to throw the light which 
comes in at the windoio up through the opening in the mid- 
dle of the stage. Do not use the direct sunlight. 

8. Place the glass slide on the stage and under the clips, 
with the object over the centre of the opening. If the ob- 
ject be mounted in a fluid, see that none of the latter oozes 
out around the edge of the cover-glass, otherwise the objec- 
tive may be soiled. Never use the high power to examine 
an object which is not protected by a cover-glass. 

9. Turn the tube down nearly to the object. 

10. While looking through the microscope, bring the ob- 
ject into focus by slowly turning the tube upward. Never 
do so by turning the tube downward. 

11. Examine every object with the low power first; keep 
both eyes open when examining an object. This can be 
done after a little practice, and avoids unduly fatiguing the 
muscles which close the unused eye. Get into the habit of 
using either eye. With the low power use a large and with 
a high power a small diaphragm. Use the concave mirror 
for strong illumination. If foreign particles appear in the 
field, locate them by the following method : While looking 
into the instrument rotate the eye-piece in the tube ; if the 
particles also rotate, they are on or in the eye-piece and 
should be removed; if the particles do not rotate, move the 
slide; if the particles move, they are on the slide and must 
be wiped off. If the object looks hazy, the particles must 
be on the objective, which may be gently wiped; if this does 
not remove the difficulty, take the instrument to the in- 
structor. While observing, vary the focus constantly with 
the fine adjustment. This method will give a far clearer 
idea of the object than to fix the focus once for all and to 
sit staring into the tube. 

12. On quitting work, turn the tube up to about an inch 
above the stage, remove the slide, unscrew the objective 
and put it into its case, remove the eye-piece and return 
it to the box, straighten the instrument if it has been in- 



INTRODUCTION XX111 

clined, and place it in the case, being careful to lock the 
latter. 

13. JVever touch the lenses or the mirror or the surface 
of the slide or cover-glass with the fingers. Wipe off dust 
with a soft cloth. Hold slides and cover-glasses by the 
edges. 



Part I 
THE BIOLOGY OF THE CELL 



I 

THE ANIMAL CELL, 
ITS MORPHOLOGY AND PHYSIOLOGY 



A. — The Unicellular Animals 
Example 1. — The Protozoa 

Material. — Specimens may be obtained in any of the 
following ways : by skimming the surface of the mud 
in the bottom of a pond or a slow -running ditch or 
brook ; by scraping the under surface of the leaves of 
water plants, as pond-lilies, duck-weed, etc. ; by squeez- 
ing the water out of clumps of fresh- water or marine 
algae, or out of damp sphagnum moss ; by tying a 
small bag of bolting -cloth or of fine muslin over the 
mouth of a Avater-tap, allowing the water to run slowly 
through the bag for fifteen minutes to an hour, then 
turning the bag wrong side out and rinsing the col- 
lected sediment into a dish containing a small amount 
of water ; by searching, under the microscope, the moist 
green film found growing on the surface of flower-pots, 
trunks of trees, and on the bricks or stones in the foun- 
dations of buildings ; by examining the fluid found in 
the mantle-cavity of oysters and clams ; by rinsing in 
artificial sea -water the gills of unboiled lobsters; by 
scraping the tongue and the roof of the mouth of frogs 



4 THE BIOLOGY OF THE CELL 

or ducks, or the gills of fishes a day or two after they 
are caught ; by rinsing the contents of the intes- 
tines of frogs, lobsters, crawfish, etc. Many marine 
forms may be caught by skimming the surface of the 
water with a net of bolting-cloth, especially on warm, 
quiet evenings. The most practicable method of sup- 
plying specimens for large classes is to resort to culti- 
vations. Fresh -water forms may be raised in large 
numbers by cutting into a dish bits of hay, grass, 
marsh-grass, potato, fish- skin, moss, or, in fact, almost 
any organic substance, pouring over the pieces just 
enough lukewarm water to cover them, and setting 
the dish, covered to prevent evaporation, in a warm, 
not too light place for one to seven days. Another 
very satisfactory method is to allow fresh- water weeds 
and algae to decay in a small amount of water. Many 
marine forms may be cultivated by soaking in artificial 
sea-water for a few days bits of oysters, clams, and the 
gills of unboiled lobsters. As particular forms usually 
have definite habitats, it is best not to obtain all of the 
specimens from a single locality, but to gather them 
from as various sources as possible. In the cultivations 
some forms will be found at the edge of the dish at the 
surface, others on the bottom, others attached to the 
sides, some swimming freely, and still others fastened 
to the pieces of organic material. 

To study the specimens properly the student will 
need the following apparatus : A compound microscope 
magnifying from fifty to four hundred diameters, slides 
and cover-glasses, and a pipette. 

Method of Examination. — Take a clean glass slide, 
with the pipette put in the centre of the slide a drop of 
water thought to contain specimens, lay a piece of hair 



THE PROTOZOA 5 

or a scrap of thin paper or a bit of wax by the edge of 
the drop, then carefully place the cover- glass on the 
drop, resting one edge upon the hair or paper so that 
the cover may not crush the specimens by its weight. 
Care must be taken to keep the specimens supplied with 
water. This can be done by placing a drop at the edge 
of the cover-glass from time to time. Capillary attrac- 
tion will draw the drop between the slide and the cover. 
Examine the preparation first with a low, then with a 
high power. Be careful not to mistake for Protozoa 
various microscopic worms and crustaceans, usually dis- 
tinguishable by their appendages. 

General Questions. — How many different shapes can 
you distinguish? What variations in size? In color? 
Is the body always symmetrical ? What determines the 
shape of the body ? Is there any distinction between 
head and body% What various motions have these ani- 
mals? By means of what organs are the movements 
produced ? Do all of the Protozoa which you find pos- 
sess the same kind of motor organ ? In what manner 
are the motor organs connected to the body ? Does the 
body contain blood% Can you find any organ corre- 
sponding to a heart ? Stomach ? Lung or gills ? Brain ? 
How do these animals eat ? Digest their food ? Breathe ? 
Are eyes present? How do the animals find their way 
about ? Do they feel ? Are nerves visible ? How do 
the Protozoa know what to eat ? Is their soft body, 
consisting mainly of protoplasm, protected in any way ? 
What means of offence or of defence have these ani- 
mals? Means of distribution? How do you account 
for their very wide distribution ? For the possibility of 
raising them artificially in the ways described above ? 

Make sketches of six of the different forms which you 
find. 



THE BIOLOGY OF THE CELL 



Example 2. — Tlie Proteus Animalcule (Amoeba Sp.) 

Material. — Good specimens may usually be found by 
scraping the slimy surfaces of water plants, washing 
damp sphagnum moss, skimming the mud in the bot- 
tom of ponds and ditches ; or raised artificially by keep- 
ing such mud, together with decaying leaves, algae, 
and other water plants, in a warm, dark place for a 
few days. Such cultivations should be closely watched, 
as Amoebce are likely to disappear rapidly in the course 
of a few days after they are first found. A little fresh 
water should be added to the cultivations from day to 
day. If Amwbce are to be kept in aquaria, be careful 
to see that all snails are removed, otherwise they may 
devour the specimens. 

The apparatus needed is the same as given for the 
general study of Protozoa, with the following addi- 
tions : camera-lucida, scale for measuring, dilute iodine, 
one per cent, acetic acid, one per cent, acetic acid car- 
mine, or fuchsin, powdered indigo or carmine, bristles, 
warm-stage, alcohol lamp, glass rod, egg, and gum-arabic. 

Method of Examination. — The same as for Protozoa. 
It is very likely that several drops of water may have 
to be examined before specimens are found. In search- 
ing for them, use the low power (f-inch or i-inch ob- 
jective) ; then study with the higher power. Take up 
a little of the sediment along with the drop of water 
to be examined. Specimens of Amoeba may be kept in 
good condition for several days in succession by placing 
them in the moist chamber. 

Having found some good specimens, study carefully 
the following : 



THE PROTEUS ANIMALCULE 



MORPHOLOGY 



a. Size. — Is Amoeba visible to the unaided eye? Com- 
pare several as regards size. Make a camera 
drawing of an average specimen and find its 
exact size, using the scale prepared for the mi- 
croscope. 

h. Shape. — What is the shape? What determines it? 
Is it constant ? Why ? Note the projections, or 
pseudopodia, of the body which are thrust out 
at intervals. How many may a single animal 
have ? How few ? What is the shape of a 
pseudopodium ? Is this shape invariable ? Do 
the pseudopodia ever branch ? Do different speci- 
mens vary in the number and size of their pseudo- 
podia ? What significance in the common name 
of the animal ? Make six sketches of the outline 
of the body at intervals of two minutes each. 

c. Structure. — Distinguish the following parts : 

1. The ectosarc (outer, clear layer of protoplasm). 

— How much of the body does it form propor- 
tionately ? Is it visible over the entire body ? 
Where is it most plainly seen? Is there any 
skin or membrane outside this layer ? 

2. The endosarc (inner, granular mass of proto- 

plasm). — How much of the body does it form ? 
Is it distinctly separated from the ectosarc? 
Compare with the latter as regards consistency. 
Does the endosarc ever appear on the outside 
of the body mass ? Are all the granules of the 
same size? What shapes and colors have they? 
Are they stationary ? Why ? What other things 
besides granules are visible in the endosarc ? 



8 THE BIOLOGY OF THE CELL 

3. The nucleus. — What is its position? Shape? 

Size ? Is it visible in each specimen ? Is it al- 
ways seen in the same place when visible at 
all ? If not plainly to be seen apply a drop of 
dilute iodine, of one per cent, acetic acid, or 
of one per cent, acetic acid carmine to one edge 
of the cover-glass, and allow the stain to run 
under the cover. Watch the effect on the other 
parts of the animal also. If the stain be used, 
fresh specimens must be prepared before going 
on with the study of the contractile vacuole. 
Do you find more than one nucleus? Is there 
a nucleolus ? In stained specimens the nucleus 
will appear darker than the surrounding proto- 
plasm. 

4. The contractile vacuole.— Position? Shape? 

Are position and shape constant in the same 
and in different specimens? Does the vacuole 
have any visible contents ? Do you find speci- 
mens having more than one contractile vacuole ? 
If there are several vacuoles, are they all con- 
tractile ? 
Make a drawing to illustrate the structure of Amoeba. 

PHYSIOLOGY 

a. Movements. — What kind of motion does Amoeba ex- 
hibit ? Is the motion continuous ? Eegular ? 
Does the body change shape when moving? 
What part of the body is used to produce move- 
ment ? Watch the manner in which a pseudopo- 
dium is formed. Is it always from the same part 
of the body ? What part does the ectosarc play 
in the process of moving ? Endosarc ? Does the 
endosarc extend into the pseudopodium ? Study 



THE PROTEUS ANIMALCULE y 

the movements or pulsations of the contractile 
vacuole. How frequent are they ? Are they reg- 
ular ? By what do they seem to be produced ? 
What becomes of the contents of the vacuole 
during a contraction ? Do the contractions affect 
the granules in the endosarc ? What do you take 
to be the function of the contractile vacuole ? Is 
it possible that it serves more than one function ? 

h. Nutrition. — What does the animal eat ? How does 
it obtain its food ? How is the food taken 
into the body? Grind a small piece of indigo 
or of carmine in water, mix a drop with that on 
the slide, and watch to see Amoeba ingest the 
particles. Note, also, the movement of these 
particles around through the body mass. Where 
is the mouth? In what part of the body is 
the food digested ? Why does not Amoeba di- 
gest itself ? How is the digested food distributed 
to different parts of the body ? Where does the 
waste matter leave the body ? In what manner 
does the animal breathe ? What breathing or- 
gans does it have ? Where are they situated ? 

c. Sensation. — If the specimens be large the cover-glass 
may be carefully removed, or a fresh specimen 
prepared without the cover, and, while examin- 
ing with a low power, the animal may be care- 
fully touched with the point of a fine bristle. 
Does Amoeba give any indication that it feels 
such an irritation ? Tap the slide with a pencil. 
How does the animal behave? Put a covered 
preparation on the warm stage, and heat slowly 
to about 45° C. What visible changes take place 
in the animal? With another covered specimen 



10 THE BIOLOGY OF THE CELL 

heat a small glass rod in the flame of an alcohol 
lamp, and touch the heated rod to the cover-glass 
in the neighborhood of the animal. What re- 
sult? 

d. Reproduction. — Look for specimens in the process of 
fission or division. If one be found, note how the 
process takes place and the length of time re- 
quired. Compare the two resulting bodies as to 
size and structure. Which is the parent ? Is the 
process preceded by sexual union? How is one 
sex distinguished from the other ? 

General Questions. — How does Amoeba protect itself 
from its enemies ? Kill an Amoeba by crushing it under 
the cover-glass. What changes take place in the proto- 
plasm ? Why does not the protoplasm of a living Amoe- 
ba go through the same changes ? Do the granules of 
a crushed Am,oeba continue to move? How does this 
movement (if any) compare with that observed in the 
living Amoeba % Compare with the crushed and with 
the living Amoeba a drop of the white of egg and a small 
piece of gum-arabic, both in water. What differences 
can you detect ? How do you explain them ? Does 
Amoeba have any organs ? Why ? 

Example 3. — The Slipper Animalcule {Paramecium Sp.) 

Material. — Specimens may almost always be found 
in water which contains a considerable amount of de- 
caying vegetable matter. They are usually abundant 
around the decaying stalks and leaves of pond-lilies. 
They may be raised in enormous number in the course 
of a week or two by placing in a warm, dark place a 
fruit -can containing water in which are dead fresh- 
water alga3 or other decaying vegetable substance. 



THE SLIPPER ANIMALCULE 11 

Use the same apparatus as for Amoeba, with one per 
cent, solution of chloral hydrate and one per cent, solu- 
tion of osmic acid additional, also a saucer and a piece 
of pasteboard. 

Method of Examination. — The same as for Amoeba. 
Paramecium is an exceedingly active animal except 
when feeding, hence it is well to have a supply of decay- 
ing vegetable tissue in the drop which is being exam- 
ined. Specimens may be brought to rest by allowing 
the water between the slide and the cover-glass slowly 
to evaporate, or they may be caught in the meshes of 
a thin layer of cotton- wool which may be spread out on 
the slide. As the cover settles down the animal will 
be caught and held fast. Care must be taken not to 
allow the cover to crush the specimen. This may be 
avoided by adding from time to time at the edge of the 
cover small drops of water just sufficient to make up 
for the loss by evaporation. Or, a drop of one per cent, 
solution of chloral hydrate or of one per cent, acetic 
acid may be added to the drop containing the specimen ; 
either of these reagents, however, will kill the speci- 
mens in the course of a few minutes. They may be 
killed in condition satisfactory for examination by plac- 
ing the slide with the drop of water downward over the 
mouth of a bottle containing a one per cent, solution of 
osmic acid. Exposure to the fumes of this acid usually 
causes the death of Paramecium in two to five minutes. 

It is best to examine the active animals before at- 
tempting to use the reagents. 

MOKPHOLOGY 

a. Shape. — What is the shape when the animal is at 
rest ? Does it change during locomotion ? Com- 



12 THE BIOLOGY OF THE CELL 

pare with Amoeba. What determines the shape ? 
Is there any variation in shape as the animal as- 
sumes different positions ? Is the body symmet- 
rical? Has the animal an anterior and a poste- 
rior end ? How are they distinguished ? What 
is the significance of the animal's common name ? 
Make drawings to show the shape of the animal 
as seen in different positions. 

b. Size. — How does Paramecium compare in size with 

Amoeba ? Examine several specimens to see if 
there are any variations in size. Is the animal 
large enough to be seen without a microscope? 
Compare length with breadth. Make a camera 
drawing of a specimen and find its actual size. 

c. Structure. 

1. The cuticle or cell- wall. — Note its extreme 

transparence and flexibility. Is it present over 
the entire surface ? Is it a complete film — i. e., 
is it entirely without openings? Place some 
specimens in a drop of water on a slide, but 
do not put on the cover-glass. Note the ap- 
pearance of the cuticle as the water evaporates 
and the body of the animal becomes dry. Can 
you discover any variations in thickness ? Any 
markings on the surface ? 

2. The ectosarc. — Is it similar to that of Amoeba ? 

Account for any differences that you may find. 

3. The endosarc— Compare with that of Amoeba. 

Look carefully for food- vacuoles — i. e., drops 
of fluid containing particles of ingested sub- 
stances. 

4. The contractile vacuoles. — How many do you 

find? Where are they situated? Examine sev- 



THE SLIPPER ANIMALCULE 13 

eral specimens to see if the vacuoles are con- 
stant in number and position. What is their 
shape when expanded ? When contracted ? 
Are they in the ectosarc or endosarc ? 

5. The nucleus (better called the macronucleus). 

— What position has it? Shape? Structure? 
If the nucleus be not easily seen, treat the 
specimen with stains as directed for Amoeba. 
After staining look for a small body, the 
paranucle us (better called the micronu- 
cleus), lying by the side of the nucleus. 
How does the nucleus of this animal com- 
pare in shape and size with that of Amoeba ? 

6. The cilia. — Are they found covering all parts of 

the body ? How do you prove this or the oppo- 
site ? Do they have any definite arrangement ? 
Are there any variations in size ? Is there any 
connection between the ectosarc and the proto- 
plasm composing a single cilium? Examine 
the form, structure, length, and diameter of a 
single cilium. This may best be done in ani- 
mals killed with one per cent, osmic acid or one 
per cent, acetic acid, or on specimens stained 
with iodine. Considering form and size, how 
many kinds of cilia can you distinguish ? Make 
enlarged drawings of the various kinds. 

7. The trichocysts (seen lying directly beneath 

the cuticle). — How are they arranged ? What 
is their shape ? Structure ? 

8. The mouth. — What is its position ? Shape? Is 

the position constant? Is the shape perma- 
nent? How is the mouth closed? Compare 
with Amoeba in these various respects. Why 
does Paramecium have a mouth ? 



14 THE BIOLOGY OF THE CELL 

9. The oesophagus or gullet. — What is its shape? 
How far does it extend? How do you distin- 
guish its lower end ? Look for cilia lining the 
gullet. 

10. The anus (seen during the ejection of waste 

matter). — Where is it ? Is its position perma- 
nent? 

11. The food- vacuoles. — In what part of the body 

are they seen ? What is their shape ? Of what 
are they composed ? Are all of the same size ? 
Compare several animals to find the average 
number contained. 
Make drawings showing the relative position, shape, 
and size of all the parts studied. 

PHYSIOLOGY 

a. Movements. 

1. Of the entire tody. — What different motions has 

the body? What are the organs of motion? 
Are all the movements of the body produced 
by these organs ? If not, how are the excep- 
tional movements produced ? 

2. Of the cilia. — What sort of motion have the 

cilia ? Is it the same for all ? What causes 
their motion ? Are all of the cilia used for the 
same purpose ? Considering use alone, how 
many kinds of cilia are there ? 

3. Of the trichocysts. — Run a drop of one per cent. 

acetic acid or of dilute iodine under the cover- 
glass. What happens to the trichocysts ? From 
their behavior when the animal is thus irritat- 
ed, what do you judge their function to be? 

4. Of the contractile vacuoles. — What sort of motion 

have they? Does each go through the same 



THE SLIPPEK ANIMALCULE 15 

movements ? What causes their motions ? Do 
they contract at the same time ? Expand ? 
"What becomes of their contents during con- 
traction? How long is the time between two 
consecutive contractions of the same vacuole ? 
Is the time uniform? Compare the rate of 
contraction or systole with that of expansion 
or diastole. Are other parts of the body affect- 
ed by the movements of these vacuoles ? The 
motions of the contractile vacuoles are often 
seen to advantage by allowing the water under 
the cover-glass to evaporate, thus causing the 
slow death of the animal. 
5. Of the food -vacuoles. — What kind of motion is 
it ? To what is it due ? Is it regular ? Do all 
of the food - vacuoles move? Do all move in 
the same direction ? At the same rate ? Are 
they affected by the movements of the con- 
tractile vacuoles ? Of what use is the motion \ 

h. Nutrition. 

1. Food and method of feeding. — Judging from the 
contents of the body, what does the slipper 
animal eat? By staining specimens with dilute 
iodine, which colors starchy substances blue and 
albuminous substances yellowish-brown, it will 
be possible to determine the nature of some of 
the ingested substances which cannot be recog- 
nized by their shape. Watch the ingestion of 
food-particles. How does it take place ? Is it 
always through the mouth ? Is there any other 
way for food to enter the body? Compare with 
Amoeba in this respect. How is the food swal- 
lowed ? Study the formation of a f ood-vacuole. 



16 THE BIOLOGY OF THE CELL 

How does it take place? How often is such 
a vacuole formed when the animal is feeding 
quietly ? What changes take place in a f ood- 
vacuole during its passage around the body? 
How is the refuse matter passed out of the 
body? What causes the changes noticed in 
the particles of food in the body ? The slipper 
animalcule may be fed with particles of indigo 
or of carmine in the same manner as described 
for Amoeba. 

e. Nervous Properties. 

1. Automaticity. — What determines the motions 

which the animal makes, the food which it se- 
lects, the times for resting or moving, etc., etc. ? 
Does it appear to perform actions " of its own 
accord " ? Is it possible to predict what the 
animal's behavior is to be at any given mo- 
ment? In what part of the body does this 
property seem to reside ? 

2. Irritability. — Does the animal appear to feel ob- 

jects with which it comes- in contact ? Does it 
respond in any way, as by movements of va- 
rious kinds, to external stimuli ? 

3. Co-ordination. — Do the cilia move rhythmically, 

or does each move independently of all the 
others? What regulates their motions? Do 
their motions seem to be made for any purpose ? 

4. Special Senses. — Do any of your observations 

lead you to think that the slipper animal has 
the sense of touch ? Does it exercise selection 
in the choice of its food — i. <?., has it the sense 
of taste ? Place a shallow dish — e. g., a saucer 
— painted black inside and then coated with 



THE SLIPPER ANIMALCULE 17 

shellac, containing a large number of slipper 
animals, near a window ; agitate the water in 
the dish so as to distribute the animals evenly. 
Cover half of the dish with some opaque ob- 
ject as a book or a piece of pasteboard, in order 
to make one side of the dish darker than the 
other. Let the dish stand quietly during four 
or five hours of daylight. At the end of that 
time examine the water carefully with a hand- 
lens to see whether the animalcules have col- 
lected more abundantly on the dark or on the 
light side. Can the slipper animal see ? 

d. Reproduction. 

1. Fission. — How does this take place ? How does 

the process begin ? How long does it last ? 
How many bodies result from it? Which is 
the " parent" and which the " child " i What 
becomes of the " ancestor " ? Is the process 
common ? How do the resulting bodies com- 
pare in shape, size, and structure with the orig- 
inal ? Can you detect, with or without re- 
agents, that any changes take place in the 
nucleus and paranucleus ? 

2. Conjugation. — How many individuals take part 

in the process ? How long does it last ? What 
portions of the body are in contact? How 
many bodies result from the process ? Is the 
process voluntary ? How are two individuals 
in process of conjugation to be distinguished 
from one individual in process of fission ? Is 
the conjugation permanent or do the individ- 
uals separate again? How are the sexes dis- 
tinguished ? Is any choice shown by those 
2 



18 THE BIOLOGY OF THE CELL 

engaged in the process? "What changes are 
noticed in the animals after conjugation ? 
Make drawings showing the process of fission in sev- 
eral different stages and of conjugation. 

General Questions. — Which is the " higher " animal, 
Paramecium or Amoeba ? Why ? What various means 
of dispersal has Paramecium ? 

Example 4. — The Bell Animalcule ( Vorticella Sp.) 

Material. — Specimens of Vorticella may usually be 
found in the water which contains Amoeba and Para- 
mecium,. Fine examples are frequently found attached 
to the stems and leaves of aquatic plants and to the fila- 
ments of algge, also to shells and stones. 

Use the same apparatus, reagents, and stains as for 
the slipper animal. 

Method of Examination. — The same as given for the 
slipper animal. 

Use in general the questions and directions given for 
the study of Paramecium, with, however, the following 
additions, the omitted numbers indicating correspond- 
ing parts of the two animals. 

Under Shape insert : — Look for colonies of Vorticella. 
Are the individuals connected in any way ? Com- 
pare the shape of the body and stalk in the ex- 
panded state with the shape of the same parts 
in the contracted condition. What is the shape 
of the body when seen from above? From 
the side? Is the common name appropriate? 
Why? 



THE BELL ANIMALCULE 19 

Under Structure insert : — 

1'. The stalk. —What is its shape? Structure? With 
what parts of the body is it connected? Ex- 
amine the axis of the stalk. Of what is it com- 
posed? Look for striations in its substance. 
Is the axis attached to the cuticle of the stalk? 
If so, in what manner ? Compare the diame- 
ter of the stalk with its length. How much 
longer is the stalk when expanded than when 
contracted ? Does the stalk correspond to any 
part of Paramecium ? 

2'. The peristome or the rim of the body. — What 
is its position? Shape? How is it formed? 
Is it complete ? 

3'. The disk (lying within the peristome). — Posi- 
tion ? Shape ? Structure ? 

7. The myophan layer or striated base of the 
bod}r. — Is it formed of cuticle, ectosarc, or en- 
dosarc? Are the striations constant? Does 
this correspond to any part of Paramecium ? 

T. The vestibule or entrance to the gullet. — Posi- 
tion? How formed? Has the slipper animal 
any part corresponding to this ? 
Make a drawing showing all of the parts visible when 
the animal is expanded ; another showing all that can 
be seen when the animal is contracted. 

Under Movements insert : — 

1. Of what use is the stalk ? Study the manner in 
which the stalk contracts. What part of the 
stalk causes the contraction? How do you 
tell? What changes take place in the body 
during contraction ? Note the rapidity of the 
movements. How does the animal assume the 



20 THE BIOLOGY OF THE CELL 

expanded condition ? What causes it ? What 
part is the first to resume the expanded state ? 
Compare the rate of contraction with that of 
expansion. Note that the body sometimes sep- 
arates from the stalk. How does the body 
move after separation ? What becomes of it ? 
What position does the stalk assume ? What 
reasons can you give for such behavior of body 
and stalk ? 

2. Ciliary movement. — What differences between 

the bell animal and the slipper animal in this 
respect? What use does Vorticella make of 
its cilia ? What is the significance of the ani- 
mal's scientific name? 

Under ^Reproduction insert : — 

3. Encystation. — Look for bell animals which have 

become encysted. How do they differ from 
the others? Of what use is this process ? What 
seems to be the cause of it ? 
Make drawings of specimens undergoing fission ; con- 
jugating; encysted. 

General Questions. — To what different uses do you 
find in general the various parts of the bell animal's 
body adapted ; in other words, to what extent do you 
find the principle of the " physiological division of la- 
bor" carried out in this simple animal? From your 
study of the Protozoa, as exemplified by Amoeba, Para- 
mecium, and Vorticella, what do you consider to be 
some of their principal characteristics and differences ? 



SALIVARY CELLS 21 



B. — Metazoa or Multicellular Animals. 

The following examples are cells from these animals, 
isolated from the body. 

Example 5.— Salivary Cells 

Material. — Rinse out the mouth two or three times 
with water, then collect some fresh saliva by spitting 
into a test-tube or a watch-glass. Let the glass stand 
quietly until the air-bubbles rise to the surface of the 
fluid and a sediment settles. The warm-stage, pipette, 
dilute iodine, magenta, one per cent, acetic acid, one per 
cent, acetic acid carmine, and indigo or carmine will be 
needed during the examination. 

Method of Examination. — With the pipette put a drop 
of the sediment on the slide and lay the cover-glass in 
position, with one edge resting on a piece of hair or a 
scrap of paper. Examine first with the low, then with 
the high power. In the preparation will usually be 
found many colorless flat cells, with irregularly polyg- 
onal outlines and large nuclei. These are epithelium 
cells from the lining membrane of the mouth, etc., and 
have nothing to do with the proper salivary cells. It 
will be well to examine their shape, size, structure, and 
the manner in which they are connected. Note also the 
very large nucleus, which may be made more distinct by 
staining with magenta or acetic acid carmine. 

MORPHOLOGY 

a. General Structure. — What is the shape of the cell? 
Size ? Color ? Does it have a cell-wall ? Nucleus? 
If so, what is its position ? Shape ? What does 



22 THE BIOLOGY OF THE CELL 

the cell contain ? Are the cells very abundant in 
the saliva ? Do they in their structure resemble 
any of the Protozoa ? 
Kun a drop of magenta under the cover -glass, and 
note the changes in the cells. Prepare another speci- 
men, and treat with dilute iodine. Test a third prepa- 
ration with one per cent, acetic acid ; a fourth with one 
per cent, acetic acid carmine. In each case note the ef- 
fect upon the entire cell and upon each of its parts. Of 
what use are these reagents and stains ? 

Make drawings illustrating the structure of the sa- 
liva cell. 

PHYSIOLOGY 

a. Motion. — Prepare another specimen as first directed, 
and place it upon the warm -stage, being very 
careful to keep the stage at the proper tempera- 
ture — i. e., that of the body. 

Does the cell have the power of voluntary 
movement? Does it have cilia? Note the pe- 
culiar dancing motion or Brownian movement of 
the contained particles. Do you find any cells 
in the process of division ? 

o. Nutrition. — Grind a little indigo or carmine in water, 
and run a drop under the cover -glass. "Watch 
the cells to see whether or not they ingest the 
particles. Note the Brownian movement of the 
particles of indigo or carmine. Do you think 
that this motion indicates that the particles are 
alive ? 
Make drawings illustrating any changes noticed in 

cells examined upon the warm-stage. 



BLOOD CELLS 23 



Example 6.— Blood Cells 

Material. — Chloroform a frog by placing it in a small 
box or under a bowl, with a piece of cloth or a small 
wad of cotton, upon either of which a few drops of 
chloroform have been poured. In four or five minutes 
the animal will be dead, though its muscles may twitch 
if stimulated. Such movements are purely reflex. Ex- 
pose the heart by making an incision with a scalpel or 
with fine scissors along the median line through the 
skin and muscles of the abdomen, and turning back the 
flaps of skin and muscle. The heart will then be seen 
beating in the pericardium. Cut into this, and lay bare 
the tip of the heart. Have at hand, also, a hand-lens, 
compound microscope, one per cent, acetic acid, strong 
aqueous solution of magenta, warm-stage, indigo or car- 
mine (dry), dilute yeast, piece of ice, alcohol lamp, .75 
per cent, salt solution, pipette, and glass rod. 

Method of Examination. — Put a drop of normal (.75 
per cent.) salt solution in the centre of a slide, lay a 
scrap of paper by the side of the drop, snip off the tip 
of the frog's heart, collect a drop of blood in a pipette 
or on the end of a glass rod, and mix the drop with the 
salt solution. Put on the cover-glass and examine with 
a low, afterwards with a high power. Lay the frog 
away on a moist cloth or sponge under a bowl so as to 
prevent the body from becoming dry. 

Eote that the blood consists of a fluid or plasma in 
which float two kinds of cell — red and colorless. 

MORPHOLOGY 

a. The red cells or red corpuscles. — Are they abun- 



24 THE BIOLOGY OF THE CELL 

dant or few in number ? What is their shape as 
seen from the side 1 From the edge ? What is 
the color ? To what is due the color of the blood 
as a mass ? Does the cell have a nucleus ? If so, 
what is its position? Does it always have this 
position? What is the shape of the nucleus? 
Structure? Has the corpuscle a wall? Is the 
cell flexible or rigid? Does the red cell bear 
any resemblance to Protozoa ? 
Make drawings of red corpuscles as seen in different 
positions, showing both shape and structure. 

b. The colorless cells or "white" corpuscles. — 

What is their shape ? Color ? Size as compared 
with the red and with one another ? Is there a 
cell-wall ? A nucleus ? How do these corpuscles 
compare in number with the red? Study this 
last point again by taking a drop of blood from 
the cut edge of a muscle half an hour after the 
incision was first made. Do you find any differ- 
ence in the number of " white " corpuscles pres- 
ent ? Compare the structure of one of these cells 
with that of Amoeba. What resemblances and 
differences do you find ? 
Make drawings showing the shape and structure of 
" white " corpuscles. 

Eun a drop of one per cent, acetic acid under the 
cover-glass. How does the acid affect the internal parts 
of each kind of corpuscle? What changes are noticed 
in the color and shape of each ? With a fresh prepara- 
tion run a drop of a strong aqueous solution of magenta 
under the cover -glass, and note the effect. Run in a 
drop of distilled water in a fresh preparation. What 
becomes of the coloring matter of the red corpuscles ? 



BLOOD CELLS 25 

Make a drawing of each kind of corpuscle after treat- 
ment with each reagent. 

PHYSIOLOGY 

Mix together on the slide a drop of frog's blood and 
a drop of normal salt solution, then examine with a 
high power. 

a. Movements. — Do any of the corpuscles have the 

power of movement from place to place, or do 
any change their shape ? If so, how is the move- 
ment effected? What sort of motion is it? Is 
it comparable to that of any animal which you 
have studied ? Put the slide on the warm-stage 
and heat to the temperature of the human body. 
Does the higher temperature make any differ- 
ence? 
Make drawings to show the direction of motion and 

changes of shape if any. 

To this drop of diluted blood add a drop of water in 

which indigo or carmine has been ground, or, better, 

use a drop of diluted yeast. 

b. Ingestion. — Do any of the corpuscles ingest the parti- 

cles of indigo or the yeast cells ? If so, how do 
they do it ? Compare with the ingestion of food- 
particles by the different kinds of Protozoa stud- 
ied. Of what use could this property of the cell 
be in the frog ? 

c. Effects of temperature. 

1. Cold. — Lay the slide on a piece of ice for five 

minutes, then examine, and compare the results 
with those of a and b. 

2. Heat. — Heat the warm-stage slowly to a degree 



26 THE BIOLOGY OF THE CELL 

uncomfortable to the touch, and note the 
changes taking place in the corpuscles. 
Make drawings to illustrate the effect of the above 
experiments. 

Example 7. — Ciliated Cells 

Material. — With a scalpel carefully scrape the roof 
of the mouth of a recently killed frog, and mount the 
scrapings on a slide in a drop of normal salt solution. 
Some single cells and some groups will be found. It 
may be necessary to use dilute iodine or one per cent, 
acetic acid carmine to demonstrate some of the struct- 
ures. Ciliated cells may also be obtained by tearing 
into fine pieces the gills of a live clam. 

MORPHOLOGY 

a. General Structure. — What is the shape of a single 
cell? How do you distinguish the upper end 
from the base? Compare several as to shape. 
Compare length with width. How are the cells 
arranged? What holds them together? Can 
you distinguish a cell-wall? Protoplasm? Nu- 
cleus? Contractile vacuole? On what part of 
the cell are the cilia ? 
Make drawings showing shape and structure of the 

cell. 

PHYSIOLOGY 

a. Movements. — What part of the cell is capable of 

movement ? Can the cell move as a whole ? If 
so, by what means ? What effect have heat and 
cold upon the movements ? 

b. Ingestion. — Can the cell ingest particles of indigo ? 



CILIATED CELLS 27 

General Questions. — In what respects does a ciliated 
cell resemble Vorticellal In what respects does the 
cell differ from the animal named ? 

From your study of the bodies of various Protozoa 
and of cells isolated from the bodies of higher animals, 
what can you give as some of the principal character- 
istics of animal cells ? Do you think that these isolated 
cells may be considered as animals ? Why % 



II 

THE PLANT CELL, 
ITS MORPHOLOGY AND PHYSIOLOGY 



A. — The Unicellular Plants 
Example 1. — Yea§t (Saccharomyces Sp.) 

Material. — Dissolve a small piece of a " compressed " 
yeast cake in a little water, put a drop of the mixture 
on the slide, and examine according to the directions 
given for Protozoa. Or, a cake of dry yeast may be 
soaked in water until soft and a drop of the mixture 
taken for examination. If baker's yeast is obtainable 
that may be used. In any case, disregard the starch 
grains which will probably be present. They may be 
recognized by being much larger than the yeast cells, 
usually oval in outline, and by having striations on 
their surface. Have at hand the magenta solution, five 
per cent, potash solution, dilute iodine, Schulze's solu- 
tion (dilute), a little corn-starch, a watch-glass, test- 
tubes, distilled water, ten per cent, sugar solution, Pas- 
teur's solution without sugar, Pasteur's solution with 
sugar, Mayer's pepsin solution, water-bath, barium 
hydrate, porous porcelain cup, litmus paper, moist 
chamber, two Florence flasks, chemical thermometer, 
teacup, alcohol lamp, dry plaster of Paris, camel's-hair 



TEAST 29 

brush, blotting-paper, absorbent cotton, U-shaped glass 
tube, baking-soda (bicarbonate of soda), and dilute 
muriatic or dilute sulphuric acid. 

MORPHOLOGY 

a. Arrangement. — How are the cells arranged? Do 

you find any single cells ? Any groups ? How 
many cells in a group ? Are the cells arranged 
similarly in the various groups ? Is this arrange- 
ment comparable to that of any Protozoa which 
you have seen ? What holds the cells together ? 
How many cells in a complete yeast plant ? 
Make drawings showing the various arrangements of 
the cells you find. 

b. Shape. — "What is it ? Is it symmetrical ? Are all of 

the cells shaped alike? Is the shape constant 
or does it change ? Compare with Amoeba and 
Paramecium. 
Make drawings of single cells showing how they 

look in outline when seen from the side and from the 

end. 

o. Size. — Is a single yeast cell visible to the unaided 
eye? With the scale measure the actual size of 
several cells. Do you find any variations in size ? 
If so how do you account for them ? 

d. Color. — What is the color of a single cell? How 

does this compare with that of fluid yeast? 
Explain. Do you detect any green coloring 
matter or chlorophyll in the cells ? 

e. Structure. 

1. The cell- wall. — Crush some of the cells by 



30 THE BIOLOGY OF THE CELL 

gently tapping or pressing on the cover-glass, 
thus squeezing out their contents. What is 
the nature of its surface ? What is its color ? 
Is the color of the cell due to the cell- wall or 
to the cell contents ? Do you find any varia- 
tions in color and in thickness ? Is there a 
mouth through which particles of food may 
enter the body ? Can you detect any especial 
place for the absorption of fluids? Do you 
find any organs of motion ? Is the wall at all 
elastic ? How do you tell ? 

2. The protoplasm. — Does it entirely fill the cell ? 

What is its color? Of what does it appear 
to consist? Examine some which has been 
squeezed out of the wall. 

3. The vacuole. — In what part of the cell is it 

found ? Do you ever find more than one ? Is 
it contractile ? Of what is it composed ? How 
much of the cell does it occupy ? 

4. The nucleus. — Is the nucleus visible in every 

cell? What is its shape? Relative size? In 
what part of the cell is it usually, found ? 

Make a drawing of a yeast cell, showing its structure 
in detail. 

Run a drop of magenta solution under the cover- 
glass and note the effect on the cells. Which stain 
soonest and most deeply ? What part of each cell be- 
comes stained, and to what extent ? On a fresh prepa- 
ration try also one per cent, acetic acid carmine. With 
another preparation run under the cover-glass a drop of 
a dilute solution of Schulze's chlor-zinc iodide. 

Treat another drop of yeast with dilute potash solu- 
tion. What happens to the cells ? 



YEAST 31 

f. Iodine test for detecting the presence of starch. 

1. Mix a little corn-starch or laundry starch in 

water in a watch-glass and add a drop of di- 
lute iodine. What is the effect on the starch ? 

2. Put on a slide a drop of water containing starch 

and examine under the microscope. What is 
the color of the starch grains? Kun a drop 
of dilute iodine under the cover-glass. What 
change takes place in the grains ? 

3. Mount a drop of yeast on a slide and treat with 

a drop of dilute iodine as above. What is the 
effect on the cells % Is starch present in the 
fluid yeast ? Is there any starch in the cells 
themselves ? 
Make drawings of the yeast cells showing the effect 
of the reagents. 

PHYSIOLOGY 

In the following experiments the amount of growth 
which has taken place may roughly be measured by the 
increase of turbidity of the liquid in the test-tubes. It 
may be tested microscopically by the number of buds 
to which the cells give rise, by the amount of proto- 
plasm, and the number of vacuoles in each cell. To 
begin with, the test-tubes must be as clean as possible. 

a. Effect of food-supply upon growth. — Take five test- 
tubes each one-third full of the solution named : 
(1) distilled water ; (2) ten per cent, solution of 
cane sugar in water ; (3) Pasteur's solution with- 
out sugar; (4) Pasteur's solution with sugar; 
(5) Mayer's pepsin solution. With a glass rod 
put a drop of yeast into the fluid in each tube, 
being careful not to lose part of the drop by 



32 THE BIOLOGY OF THE CELL 

touching it against the side of the tube, shake 
the tubes thoroughly, tightly plug the mouth of 
each with a wad of clean absorbent cotton, to 
prevent the entrance of dust, and set them in 
the water-bath, heated to 35° C, for two or three 
days. Examine the tubes from time to time and 
notice what is taking place. More accurate re- 
sults may be obtained in the following manner : 
Prepare five moist chambers, using a drop of 
each of the culture fluids given above, mix one 
drop of fluid yeast with about a thimbleful 
of distilled water, then mix a drop of this 
diluted yeast with the drop of culture fluid 
in the moist chamber, and watch under the 
microscope from day to day the development of 
the yeast cells in each kind of fluid. In which 
solution does the yeast grow best? In which 
solutions are bubbles of gas formed ? Can you 
detect any relationship between the number of 
bubbles formed and the amount of growth? 
What relationship is there between the compo- 
sition of the various solutions and the amount of 
growth which takes place in each? Is growth 
accompanied by anything else than the increas- 
ing turbidity of the solutions and the formation 
of bubbles ? Do you find anything besides yeast 
cells growing in these solutions ? If so, how do 
you distinguish them from yeast and how do 
you account for their presence ? In what condi- 
tion must the food be in order that it may be 
absorbed? Why does the cell absorb "food 
solutions " ? Through what must the absorbed 
substances pass in entering the cell ? 

Taste of the ten per cent, sugar solution after 



YEAST 33 

the yeast has been growing in it for a day or 
two. Compare with some in which there has 
been no yeast. What difference do you find ? 
How do you account for it ? Test the two solu- 
tions with blue litmus paper (which turns red 
when placed in an acid). What result ? Explain. 
Make a thick syrup of sugar and water, put some 
into a test-tube, mix a drop of yeast with the 
syrup, and set the tube in the water-bath for a 
day. Does the syrup ferment? Can you ex- 
plain why % Can you explain why canned fruit 
frequently " sours " while preserves do not ? 

b. Effect of temperature upon growth. — Fill each of three 

test-tubes one -third full of Pasteur's solution 
with sugar, into each put a drop of fluid yeast, 
and close the mouth of the tube with a plug of 
cotton-wool. Set the first tube in some place, 
as in the water -bath, where the temperature 
can be kept constantly at about 35° C. Boil the 
contents of the second tube for two or three 
minutes, then set this tube with the first. Put 
the third tube on a block of ice or in a dish of 
ice-water. Examine each tube two or three 
times a day for several days and note what 
takes place. Explain your results. What is the 
effect of a very high temperature, i. <?., boiling ? 
Of a very low temperature, i. <?., freezing ? 

c. Effect of light upon growth. — Prepare two test-tubes 

with Pasteur's solution and a drop of yeast as in 
b. Wrap one tube with thick paper so as to ex- 
clude the light. Leave the other unwrapped. 
Set the two tubes side by side in a window where 
3 



34 THE BIOLOGY OF THE CELL 

they will be exposed to the sunlight. Examine 
the tubes from time to time for two or three days. 
In which tube does the yeast grow better ? Has 
sunlight any effect upon the growth of yeast ? 

d. Nature of the gas given off by the growing yeast. 

1. Take two test-tubes, a perforated cork which will 

fit one of the test-tubes, and a U-shaped glass 
tube, one branch of which is passed through 
the perforation in the cork. Fill the first test- 
tube one-third full of clear baryta water, or 
lime-water may be used if necessary ; into the 
second test-tube put some baking-soda or bicar- 
bonate of soda (which is a combination of so- 
dium and carbon dioxide, or " carbonic- acid 
gas ") ; pour into the second test - tube a few 
drops of dilute muriatic or of dilute sulphuric 
acid ; insert the cork at once in such a manner 
that the end of one arm of the U-shaped tube 
is above the surface of the fluid in the test-tube ; 
hold the first test-tube in such a manner that 
the end of the other arm of the U-shaped tube 
will extend below the surface of the baryta 
water in this test-tube. The gas (carbon diox- 
ide) formed in the second test-tube by the 
action of the acid upon the soda will thus be 
carried by the U-shaped tube over into the first 
test-tube, where it will bubble up through the 
baryta water. What change takes place in the 
baryta water ? 

2. Pour some clear baryta water into a watch-glass, 

and, holding the mouth close to the surface of 
the liquid, breathe heavily through the mouth 
upon the surface of the water. What change 






YEAST 35 

takes place in the water % Is this result at all like 
that obtained in the first experiment ? Explain. 

3. Take two test-tubes, prepare the first with baryta 

water as in the first experiment, fill the second 
test-tube about half full of yeast which is ac- 
tively giving off bubbles of gas, connect the 
two tubes as before so that the gas will bubble 
up through the baryta water. If the gas stops 
forming, add a little sugar to the yeast. Does 
the baryta water change as in the first experi- 
ment ? As in the second ? Is, then, the gas 
which is given off by a liquid in which yeast is 
growing the same as the gas formed by the ac- 
tion of an acid upon bicarbonate of soda, and 
also the same as that exhaled from the human 
lungs ? 

4. Put a half - teacupf ul of actively growing yeast 

into a loosely corked bottle, and set the bottle 
in a warm place for an hour or so. Is the cork 
blown out ? "Why ? Prepare another bottle in 
a similar manner, but tie the cork down with 
a cord or wire. Do bubbles of gas still form 
in the fluid? What do you conclude, then, 
regarding the energy with which the gas is 
formed in the fermenting liquid, in spite of the 
pressure on its surface due to the accumulation 
of gas in the upper part of the bottle? The 
pressure of the accumulated gas may be meas- 
ured directly by means of a manometer. This 
consists of a U-shaped tube partially filled with 
mercury. First mark the level of the mercury 
in the two branches; then, by means of a rub- 
ber tube, connect one branch with a glass tube 
run through the stopper of the bottle of yeast. 



36 THE BIOLOGY OF THE CELL 

The gas will come through the glass tube and 
the rubber tube over to the surface of the mer- 
cury in one branch of the manometer, and push 
down the mercury on that side and raise that 
on the other. Measure the height of the mer- 
cury, and calculate the pressure needed to raise 
the column of mercury to this height. 

e. Formation of alcohol. — Grow some yeast in Pasteur's 

solution with sugar, in a flask closed with a cork 
through to the lower surface of which passes a 
glass tube about eight inches long, bent down- 
ward at an angle of about 30°. When the forma- 
tion of gas has entirely ceased in the flask, set 
the latter on a water-bath and, at the lowest tem- 
perature possible, distill the fluid into a test-tube 
held at the end of the bent tube. When the test- 
tube is about half full, remove the stopper and 
bent tube from the flask, insert them into the 
test-tube, and redistill the contained fluid, collect- 
ing the first few drops in a watch-glass. Do they 
give off the odor of alcohol ? Apply a lighted 
match to the fluid in the watch-glass to see if it 
ignites and gives the pale blue flame characteris- 
tic of burning alcohol. 

f. Chemical reaction of fluid yeast. — Dip the end of a 

strip of blue litmus paper (which turns red when 
placed in an acid) into some fluid yeast. What 
change takes place in the color of the paper ? Is 
fluid yeast acid or alkaline in its nature? Note, 
also, the odor of the fluid. 

g. Temperature of yeast during growth. — Take two 



TEAST 37 

Florence flasks (bottles may be used), and into 
each put about one litre of Pasteur's solution 
with sugar. Into the first put also 200 c.c. of 
fresh yeast. Close the mouth of each flask with 
a plug of cotton -wool. Wrap each flask in a 
cloth, or, better, in cotton, and put them side by 
side in a box to protect them from draughts. 
When fermentation becomes vigorous in the first 
flask, as will be indicated by the formation of 
bubbles of gas, take the temperature of the liquid 
in each flask with a good thermometer and com- 
pare the results. In which flask is the tempera- 
ture higher ? Let the flasks stand until about ten 
or twelve hours after the formation of bubbles 
has ceased in the first flask, and then take the 
temperature again. Was the difference in tem- 
perature first noticed due to the presence of yeast 
or to its growth ? Why ? 

h. Effect of filtered yeast upon a fermentable fluid. — 
Sterilize a small porous porcelain cup, such as is 
used in batteries, by boiling it in water for sev- 
eral minutes. Set the porous cup into a teacup 
which has also been boiled, and fill the porous 
cup about half full of fluid yeast. In a short 
time some of the fluid part of the yeast will filter 
through the porous cup, leaving the solid part 
(yeast cells) behind, and will be caught in the tea- 
cup. Fill a test-tube one -third full of Pasteur's 
solution with sugar, plug the mouth of the tube 
lightly with cotton -wool, and sterilize the con- 
tents by boiling for about five minutes over the 
flame of an alcohol lamp or a Bunsen burner. 
Allow the fluid to cool, then with a glass rod, 



38 THE BIOLOGY OF THE CELL 

which has been sterilized by being passed through 
the flame of the lamp, take up a few drops of the 
fluid in the teacup, and mix them with the Pas- 
teur's fluid in the test-tube. Set the test-tube in 
a warm place, e.g.,35°C, for a few hours, exam- 
ining from time to time to see if bubbles of gas 
are formed. Is the actual presence of yeast cells 
necessary to produce fermentation, or is there 
something in the fluid in which yeast cells have 
lived which will bring about that change? If 
the latter, whence does that something — i. e., en- 
zyme or ferment — probably come ? 

i. Reproduction. 

1. Budding or gemmation. — Examine cells from 

each of the cultures made in the experiment 
on the effect of food-supply upon growth. In 
which have the cells the largest number of 
buds ? In which the smallest ? How many 
buds may a cell have? Do all the cells have 
buds? Can you always distinguish which is 
the " parent " and which is the " bud " ? Are 
the buds always formed on the same part of the 
cell ? What are the steps in the process of the 
formation of a bud ? "What is the difference 
between reproduction by budding and repro- 
duction by fission? Is the difference funda- 
mental ? 
Make drawings to show how buds are formed and how 
they are attached. 

2. Endogenous spore-formation. — Make a slab of 

plaster of Paris about one-fourth of an inch in 
thickness and about two inches square. Upon 
one face of this paint with a clean camers-hair 



GREEN SLIME 39 

brush a thin layer of yeast taken from a sup- 
ply which is actively growing. Put the slab 
under a bell-jar or a tumbler with some pieces 
of wet blotting-paper to keep the air moist. 
With the point of a penknife or scalpel remove 
some of the cells each clay for eight to fourteen 
days, and examine under the high power of the 
microscope for spores formed inside the cell. It 
is well to make several such cultures, as some 
are almost certain to be spoiled by the growth 
of moulds and bacteria. Compare with the 
process of budding. Do you find any relation 
existing between nutrition and reproduction? 
Do you find any evidence of the conjugation 
of individual plants ? 
Make drawings illustrating endogenous spore-forma- 
tions. 

General Questions. — Compare the results obtained in 
all of your work on this plant, and tell what yeast 
forms from its food. 

Of what use is yeast in bread-making ? In brewing? 
Is yeast a " cultivated plant " ? If so, how is it culti- 
vated and what is the " soil " upon which it grows ? 

Example 2. — Green Slime (Protococcus Sp.) 

Material. — Specimens of green slime, or of other uni- 
cellular green plants which are so closely related to the 
form selected as to be equally serviceable, may be found 
almost everywhere, forming a greenish, slimy ooze on 
the surface of the mud and stones in the bottoms of 
slow- running ditches, on the trunks of trees near the 
ground, on the stones or bricks in the foundations of 



40 THE BIOLOGY OF THE CELL 

buildings, on the outside of damp flower-pots, etc. They 
will be most easily found after a few days of rain ; at 
other times their bright green color is likely to be dingy 
and not so noticeable. If the plants be found on a tree, 
cut off pieces of the bark and put them in a saucer with 
a little water to moisten the bark, cover with a tumbler, 
and set them in a window where they will have the 
sunlight. In this manner a supply of fresh specimens 
may be kept for a long time and the various stages of 
growth studied from time to time. This method of 
procedure is advisable, as it is sometimes impossible to 
lincl material showing both the vegetative and the re- 
productive stages of the plant. Besides the specimens, 
the student will need strong iodine, alcohol, seventy-five 
per cent, sulphuric acid, dilute chlor-iodide of zinc, and 
a compound microscope ; also some cotton fibres, which 
are best obtained from a cotton-boll, as they have then 
passed through none of the processes incident to manu- 
facture, and are in a perfectly natural condition. If the 
boll cannot be obtained, fibres from a thread or from a 
piece of cotton cloth may be used. 

Method of Examination. — Before resorting to the 
microscope examine, as directed on page 41, the naked- 
eye characters. If the material be obtained from a very 
damp situation, a small piece of the mud or of the film 
of slime may be put upon the slide, in a drop of water, 
and torn to pieces with the dissecting needles, so as 
to separate the cells of the plant from the tangle of 
thread -shaped algee and fungi, associated with which 
the green slime almost always grows. If the material 
be dry and powdery, as it is likely to be if obtained 
from bark in dry weather, a little of the film may be 
scraped into a drop of water on a slide by means of 



GKEEN SLIME 41 

the needle point or a scalpel. The cover -glass may 
then be put on and the specimen examined as usual. 

MORPHOLOGY 

Naked-eye Characters : 

a. Occurrence. — In what other places than those men- 

tioned above do you find the plant ? If found in 
ditches, do you get it most abundantly in muddy, 
sandy, or rocky places ? If on flower-pots, on the 
lighted or shaded side ? If on trees, does it grow 
better on those with rough or on those with 
smooth bark ? Why ? Does it show preference 
for the north, east, south, or west side ? Why ? 
Is the film even in thickness, or do you find 
marked variations in this respect ? 

b. Color. — What is the usual color? Are specimens 

from different situations always of the same 
color? If you find variations, how do } x ou ex- 
plain them? Put under a tumbler or a bell-jar 
and keep moistened a piece of dry bark bearing 
green slime. Does the color change at all ? Put 
into a small bottle of alcohol a piece of clean 
bark upon which green slime is growing and 
leave for a few hours, then remove the bark from 
the bottle. What change, if any, has taken place 
in the color of the green slime ? In the alcohol ? 
Explain. 

c. Structure. — Scrape the film off a piece of dry bark. 

Does it adhere firmly to the bark ? Does it sep- 
arate into large or small flakes ? Do the flakes 
hold together well, or do they break up into 
small particles? Scrape a film off a piece of 



42 THE BIOLOGY OF THE CELL 

damp bark, examine, and account for any differ- 
ences you may find. 

Microscopic Characters : 

Examine first with a low, then with a high power 
specimens prepared as directed. 

A. Vegetative Condition. 

a. Arrangement. — Do you find groups of cells ? Single 

cells ? What various numbers of individual cells 
do you find constituting different groups? Are 
the cells arranged at all as in yeast ? 
Draw single cells and groups. 

b. Shape. — What is the shape of a single cell? Is the 

shape symmetrical or irregular ? Do you find any 
noticeable variations ? How is the shape of the 
individual cell modified where the cells occur in 
groups? Compare the shape with that of the 
yeast cell. Does it have a greater variety of 
shapes than the latter ? How do you account for 
them ? Does the cell have outgrowths or pro- 
jections of any kind, such as roots? How does 
green slime remain attached to the surface of the 
bark or stone? Has it any organs of motion? 
Does it resemble in shape any of the Protozoa f 
Draw several specimens showing marked variations 
from the normal shape. 

c. Size. — Do the cells vary much in size ? Measure sev- 

eral and find the average dimensions. How do 
they compare in size with yeast ? With the slip- 
per animal? With the red corpuscles of the 
frog? 

d. Color. — What is the color as seen under the micro- 



GREEN SLIME 43 

scope? Is it different from that seen with the 
unaided eye? Is the color evenly distributed 
throughout the cell ? Do you find cells showing 
more than one color ? Examine some cells taken 
from the piece of bark which was put in alcohol, 
and compare them with the fresh cells. 

e. Structure. 

1. The cell- wall. — Is its surface smooth or rough? 

Is the wall thicker or thinner than that of a 
yeast cell? Are there any variations in thick- 
ness ? Is the wall colored ? 

2. The cell-contents. — Can you distinguish proto- 

plasm in the cell ? Nucleus ? Vacuole ? Chro- 
matophores (chlorophyll bodies, or green 
masses of protoplasm) ? Kun a drop of strong 
iodine under the cover-glass. What effect has 
it on the protoplasm of the cell? Does it 
show the presence of starch grains in the cell? 
"What effect has it on the cell- wall? Apply 
to the same specimen a drop of seventy-five per 
cent, sulphuric acid. Do you notice any change 
in color in the cell-contents? In the wall? 
Make a fresh preparation of the plant and ap- 
ply a drop of dilute chlor-iodide of zinc. How 
are the cell-contents and the wall affected ? Let 
the specimen stand for an hour or two, then 
examine again. Do you notice any important 
changes, especially in the chromatophores ? 
Make drawings to show the structure of a single 
cell. 

f. Tests for cellulose. 

1. Put some cotton fibres (which are almost pure 
cellulose), into a drop of water on the slide, put 



44 THE BIOLOGY OF THE CELL 

on the cover -glass, and examine. Note the 
shape, color, and structure of the fibres. 

2. Kun a drop of strong iodine under the cover- 

glass. What is the effect upon the fibres ? 
Compare with the same treatment of the cell- 
wall of green slime. 

3. Follow the iodine with a drop of seventy-five per 

cent, sulphuric acid. "What change ? Compare 
with the preceding experiment and with the 
color of the green slime after such treatment. 
The preceding and this experiment together con- 
stitute the iodine-sulphuric acid test for cellulose. 
How does it differ from the test for starch ? 

4. Mount some cotton fibres as in the first experi- 

ment, then run under the cover-glass a drop of 
dilute chlor-ioclide of zinc. What is the effect 
upon the fibres ? Compare with that produced 
by iodine and sulphuric acid used together, and 
with the effect upon the wall of the cells of 
green slime. Is the cell -wall of green slime 
composed of cellulose ? 

B. Reproductive Condition. 

In addition to the motionless or vegetative cells, 
certain others, the zoospores, will probably be 
found actively moving about. If they are not 
found in the material when first gathered, they 
are likely to appear if water containing the vege- 
tative cells be left exposed to the sunlight for a 
few days. The zoospores are of two sizes, the 
larger being called macrozob spores and the 
smaller microzobspores. Examine the shape, 
size, and structure of each. Try to find vegeta- 
tive cells whose contents are dividing into 2-4 



GREEN SLIME 45 

parts or macrozoospores, or into several parts or 
niicrozoospores. ISTote the cilia with which the 
zoospores of each kind are provided. How many 
cilia do you find on each? Are they of equal 
length ? If the cilia are indistinct, the cells may 
be stained with dilute iodine. Can you discover a 
cell- wall around the protoplasm of the zoospores ? 
Do you find that the zoospores unite? Is the 
movement of the cells rapid or slow ? Why should 
these reproductive cells be motile, while the veg- 
etative cells are motionless? Look for zoospores 
which have come to rest. Can you determine 
whether or not they have a cell -wall, using re- 
agents if necessary ? Can you distinguish such a 
zoospore from a vegetative cell? In what ways 
do the zoospores resemble any of the JProtozoa, 
especially in structure ? Do they exhibit any ner- 
vous properties, such as automaticity, irritability, 
etc.? Examine the dish of water in which the 
zoospores were found, or transfer water contain- 
ing them to a dish and place the dish in the sun- 
light for a few hours, then examine a drop of 
water taken from the side of the dish towards 
the light and another from the side away from the 
light. Which drop contains the greater number 
of zoospores? Having obtained a definite answer 
to this question, stir the water thoroughly, so as to 
distribute the cells evenly through it, then trans- 
fer the dish to a place out of the direct sunlight, 
preferably several feet from the window, and let 
it stand for several hours. Then examine two or 
more drops taken from opposite sides of the dish as 
before. Do you find any difference in the position 
of the zoospores ? If so, how do you explain it ? 



46 THE BIOLOGY OF THE CELL 

Make drawings to illustrate as many as possible of 
the facts yon have learned concerning the reproductive 
stage of green slime. 

General Questions. — In what ways may green slime 
be dispersed? Is green slime dependent upon "food 
solutions" for its nourishment? If not, how can it, 
having no roots, get food ? Which do you regard as 
the higher plant, green slime or yeast ? Why ? 



B. — Multicellular Plants 

The following examples are cells from these plants, 
isolated from the body : 

Example 3. — Spores of Fungi (Penicillium, Eurotium, Aga- 
ricus, etc.) 

Material. — If no bread, cake, jam, or leather bearing 
mould can be obtained, a slice of bread or cake or a 
few dried prunes may be put on a saucer under a bell- 
jar or tumbler with a few scraps of moist blotting-paper, 
and set away in a warm place. Moulds will usually ap- 
pear in the course of a few days. Specimens may also 
be obtained frequently from the top of canned fruit and 
preserves. In case mouldy substances fail, the top of a 
ripe mushroom or toadstool which may be had at green- 
houses at almost any season will do as well. Iodine, 
acetic acid carmine, magenta, Pasteur's solution with 
sugar, compound microscope, bell -jar, and the moist 
chamber will be used in the examination of the ma- 
terial. 

Method of Examination. — Hold a piece of the mouldy 



SPOKES OF FUNGI 47 

material over a drop of water on a slide, and by gently 
tapping the mouldy substance dust some of the spores 
into the drop. Put on the cover-glass, supporting it at 
one edge by a piece of hair, and run a drop of fifty per 
cent, alcohol under the cover -glass, as water alone does 
not wet the surface of the spores. 

MORPHOLOGY 

a. General Structure. — To the unaided eye what appear- 
ance have the spores? Are they numerous or 
few ? What color has a mass of spores ? Exam- 
ine first with a low, then with a high power. 
What is the shape of the spores? Are they sepa- 
rate or connected ? Can you distinguish, with or 
without the use of iodine, acetic acid carmine, 
magenta, etc., whether or not the cells have wall, 
protoplasm, chromatophores, nucleus, etc. ? In 
what respects do these spores resemble yeast 
cells ? In what respects do they differ from the 
cells of green slime? How do you account for 
the wide dispersal of the spores of moulds ? 
Make drawings to illustrate shape, size, and structure. 

PHYSIOLOGY 

a. Germination. — Dust some spores into a drop of water 
and with the point of a needle transfer a small 
portion, so as to get as few spores as possible, to 
a drop of Pasteur's solution with sugar in a moist 
chamber, and examine at intervals for several 
days. Unless great care is taken foreign organ- 
isms — bacteria, etc. — are likely to interfere with 
the growth of the spores. The following method 
of preparation will probably give good results : 



48 THE BIOLOGY OF THE CELL 

Boil a small amount of Pasteur's solution or of 
dilute prune-juice, and with a glass rod, which 
just before using has been passed slowly through 
the flame of an alcohol lamp, transfer a drop of 
the fluid to the surface of a cover-glass which 
has likewise been passed through the flame ; have 
ready the glass slide, which previously has been 
sterilized in the same manner, and lay on it the 
card-board cell or glass ring, which has been ster- 
ilized in boiling water; invert over the cell as 
quickly as possible the cover-glass with the hang- 
ing drop, and after making sure by microscopic 
examination that spores, drop, etc., are in good 
condition, set the slide away under a bell-jar in a 
warm place. Note how the spores sprout. How 
long before the process begins? What is the 
first indication that a sprout is forming? How 
does the size of the tubes put forth compare with 
that of the spores ? How do you account for the 
difference ? 
Make drawings to illustrate different stages of germi- 
nation. 

General Questions. — Upon what do the spores depend 
for their dispersal ? How do you account for the mould- 
ing of bread, pastry, leather, ink, etc., in warm, damp 
weather? Why does it not also happen as frequently 
in cold weather ? How is it possible for fruit in closed 
cans to become mouldy ? 

Example 4. — Pollen Grains 

Material. — The best plan will be to get pollen from a 
number of flowers and make a comparative study. It 



POLLEN GRAINS 49 

is immaterial whether the flowers be wild or cultivated, 
but as the latter are always to be had a few common 
kinds may be mentioned as suitable: Sweet -pea (Za- 
thyrus), Evening Primrose (CEnothera biennis), Willow- 
herb (Ejpilobium), Fuchsia, Hollyhock (Althcea rosea), 
Mallow (Malva crispa), Onion (Allium), Tulip, Tiger- 
lily, Japanese Lily, Hyacinth, Gloxinia, Poppy (Papa- 
ver), Pansy ( Viola tricolor), or Chicory [Cichorium inty- 
bus). The anthers of the flowers should be examined, 
with a hand-lens if necessary, to see if they have 
opened. If so, the pollen is in proper condition for 
study, and will usually appear as a yellow, white, or 
brown powder. 

In the examination may be used iodine, Schulze's 
solution, potash, acetic acid carmine, and sugar. 

Method of Examination. — "With the point of a needle 
remove a little of the pollen to a slide, and examine first 
in the dry state — i. e., without the drop of water and the 
cover-glass. Afterwards prepare the pollen in the drop 
of water in the usual way. Note particularly the differ- 
ence in the appearance of the same kind of pollen ex- 
amined in each of these ways. 

MORPHOLOGY 

a. General Structure. — Do you find that the individual 
pollen grains are visible to the unaided eye ? Do 
you find any variety of shape, size, color, and 
structure? Do you find that the color of the 
individual grain is the same as that of a mass 
of the same grains? What do you find in the 
way of markings, grooves, wing-like expansions, 
points, etc., on the wall of the grains? Can you 
4 



50 THE BIOLOGY OF THE CELL 

determine the use of any of these ? "What means 
of protection from being dried, eaten by insects, 
attacked by parasitic fungi, etc., do the pollen 
grains exhibit ? Examine the stigmas or tips of 
the pistils of the flowers of several different kinds 
of plants, and note the presence of pollen grains 
in some if not in all cases. Do you find in any 
case that the pollen grain has means of its own 
for getting from the anther to the stigma — i. e., 
has it any organs of motion ? If not, how does 
it make its way from one part of the flower to 
the other % Examine the grains for the presence 
of protoplasm, nucleus, chromatophores, oil drops, 
etc., using reagents if needed. 
Draw several specimens to show the variations in 
shape, size, and markings. 



PHYSIOLOGY 

a. Germination. — Make a dilute syrup or nectar by 
placing seven or eight crystals of "granulated" 
sugar in a drop of water on the slide. When 
they have dissolved, dust into the drop a few 
grains of pollen from some of the flowers named 
above, preferably the Sweet-pea. Let the grains 
remain in the syrup for several hours, examining 
from time to time to study the formation of the 
pollen tube. Note its size and rate of growth in 
different grains. Compare with the germination 
of the spores studied in Example 3, and note all 
of the resemblances and differences that you can 
discover. Much more successful cultivations may 
be made in a hanging drop in a moist chamber. 
Pollen grains which have germinated under natu- 



WATER SILK 51 

ral conditions may be found by examining the 
stigmas of various flowers with a hand- lens, espe- 
cially lilies, hyacinths, fuchsias, etc., and having 
found a stigma to which grains are attached, re- 
moving them to the drop of syrup prepared as 
above. 

Do you find variations in the time it takes 
seemingly mature grains to germinate? Is the 
pollen tube single or many celled ? 
Make drawings to illustrate the different stages of 
growth in pollen grains of the same kind and of differ- 
ent kinds. 

Example 5.— Water Silk {Spirogyra Sp.) 

Material. — The study of this plant is introduced here 
because its cells are so large and lend themselves so 
readily to manipulation that they form most desirable 
material for the study of the structure and functions of 
the plant cell. 

These plants may be obtained in abundance during 
the warm season of the year in almost any stagnant 
pond or along the edges of slow-flowing streams. They 
form the yellowish-green, frothy scum popularly called 
" frog -spittle" or "pond -scum." Various species are 
usually found growing together, along with other fresh- 
water algge. Almost any species will serve for study, 
but the larger kinds are especially favorable. They 
may be kept for examination in winter in aquaria with 
opaque sides, which should be placed in sunny windows, 
be supplied with fresh water from time to time, and 
kept partially covered to exclude the dust. In chang- 
ing the water be careful to disturb the plant as little 
as possible. If it be found that the water is becoming 
infested with too many micro-organisms, transfer some 



52 THE BIOLOGY OF THE CELL 

of the material to a jar of fresh water. Under such 
conditions of cultivation the plants will go through 
their fruiting stages nearly all winter. If it be imprac- 
ticable to keep living plants for study, specimens may 
be preserved in fair condition, though the color will be 
lost, in a mixture of equal parts of water, glycerine, and 
alcohol. 

The following study requires the use of the hand- 
lens, compound microscope, fine forceps, seventy-five per 
cent, sulphuric acid, Schulze's solution, dilute iodine, pi- 
cric acid, strong potash solution, ninety per cent, alcohol, 
carmine, magenta, two per cent, salt or sugar solution, ten 
per cent, salt or sugar solution, twenty per cent, salt or 
sugar solution, a vial or test-tube, distilled water, Sachs's 
food-solution, ice, and a saucer. 

Method of Examination. — The plants should first be 
studied in their native pool, their surroundings and hab- 
its noted, etc. Then examine some as they grow in an 
aquarium. Then, with the forceps, transfer one or two 
filaments to a porcelain bowl or saucer in which the 
dark green of the plants will show well against the 
white background formed by the saucer. For the mi- 
croscopic study only two or three filaments should be 
placed on the slide, where they may be studied with 
the hand-lens and with both low and high powers. 



MORPHOLOGY 

A, — Vegetative Condition. 
I. Naked-eye characters. 

Examine some of the plants as they grow in 
the aquarium, particularly the position occupied 
by the mass after exposure to sunshine for a few 



WATER SILK 53 

hours, and again the next morning before the sun- 
light reaches the aquarium, and by individual fil- 
aments. Put several filaments into a saucer of 
water and note their shape, color, length, and 
diameter. What variations do you find in these 
features? If necessary use a magnifying-glass. 
Does the plant grow attached to a substratum ? 
Can you see any branches ? Eoots ? Why is the 
plant an inhabitant of stagnant water ? Feel of 
the plants. What significance in the common 
names ? 

II Microscopical characters. 

Mount two or three filaments in water and ex- 
amine first with a low, then with a high power, 
and note : 

a. The shape of the filament. — What is it ? Is its diam- 

eter uniform ? What is the shape of the ends ? 
Can you detect any branches or roots ? Has it a 
" root end " and a " stem end " ? 

b. The structure of the individual filament. — Note that 

the filament is composed of cells. How are the 
cells arranged? What is the shape of a single 
cell? What relation between its length and 
breadth? Are all of the cells of this shape? 
How are the cells connected ? Is there any dif- 
ference between the two ends of the filament? 
Be careful not to be deceived by injured cells, 
which are frequently to be found at the end of 
the filament. Look for a transparent, slimy coat- 
ing covering the filament. This is seen best just 
before a drop of stain reaches the filament. How 



54 THE BIOLOGY OF THE CELL 

do you account for the slippery feel of the 

plant? 

c. The structure of the individual cell. 

1. The cell- wall. — What is the shape of the side- 

wall ? Of the end-wall ? . What is the color of 
the cell- wall ? Which is the thicker, the side- 
wall or the end-wall ? Do you find any open- 
ings in either wall ? Markings of any kind on 
the wall ? Run a drop of strong iodine under 
the cover-glass, then a drop of seventy-five per 
cent, solution of sulphuric acid, and note the 
effect upon the cell -wall. Of what is it com- 
posed ? Try also Schulze's solution. Treat a 
fresh preparation with strong potash solution, 
and note the stratification of the wall. How do 
you account for this appearance ? 
Take another fresh preparation and examine 

2. The chromatophores or chlorophyll bodies. 

— What is their arrangement ? General shape ? 
What is the shape of their margins ? How many 
in a cell \ How many turns does each make ? 
In what part of the cell do they lie ? Do they 
extend from one cell into the next? What 
is their color? Are there any other colored 
bodies in the cell ? Do these chromatophores 
in any way resemble the green part of the cell 
of Protococcus ? To what is due the color of 
the plant as a whole? What significance in 
the scientific name of the plant ? Put some 
filaments into strong alcohol and examine 
them after a few hours. What change in the 
chromatophores? In the alcohol? Explain. 
Stain some of the filaments with carmine or 



WATER SILK 55 

magenta, which are substances which stain 
protoplasm especially. What is the effect on 
the chromatophores ? On the cell-wall ? Of 
what substance are the chromatophores com- 
posed ? 

3. The pyrenoids and starch grains (seen in the 

chromatophores). — Apply picric acid to make 
the pyrenoids more plainly visible. How are 
the pyrenoids arranged ? What is their color ? 
Shape ? Run a drop of iodine under the cover- 
glass and note the position and number of the 
starch grains. What is their relation to the 
pyrenoid ? Do they at all affect the shape of 
the chromatophore ? Examine some of the 
cells treated with alcohol in the second experi- 
ment. Does carmine or magenta stain the 
pyrenoid ? Of what substance is the pyrenoid 
composed ? Treat with iodine some other cells 
which have been in alcohol. Is starch still 
present in these cells ? Explain. Do you find 
starch grains anywhere else than in the neigh- 
borhood of the pyrenoid ? 

4. The nucleus. — What is its position in the cell? 

Shape? Color? Can you find the nucleolus? If 
so, what is its position ? Shape ? In which cells 
is the nucleus seen most distinctly ? Notice the 
strands of protoplasm radiating from the nu- 
cleus. To what do they run ? How many can 
you find ? Examine the nucleus in cells treated 
with alcohol, iodine, magenta, etc. 

5. The primordial utricle or protoplasmic sac. 

— Try to see this (without using reagents) as a 
thin film of protoplasm lining the cell-wall. If 
unsuccessful, plasmolyze the cell by running a 



56 THE BIOLOGY OF THE CELL 

drop of ten per cent, salt or sugar solution un- 
der the cover-glass, and note how the proto- 
plasm shrinks away from the cell-wall. What 
is the cause of the shrinkage of the protoplasm 
when the cell is plasmolyzed ? What proper- 
ties of protoplasm does the experiment illus- 
trate ? What becomes of the chromatophores ? 
What change takes place in the cell- wall? Try 
plasmolyzing the cell with a twenty per cent, 
solution of salt or sugar. What difference in 
the action of this and of the weaker solution ? 
Plasmolyze with a two per cent, salt solution. 
As soon as the protoplasmic sac shows plainly, 
remove the salt solution and replace it with 
water. Does the sac expand until it again fills 
the entire cell? Explain. Explain all of the 
changes noticed. 
6. The vacuole. — Note that a large part of the cell 
is occupied by the vacuole. What change takes 
place in this when the cell is plasmolyzed ? Ex- 
plain. Examine several cells to note the varia- 
tion in the size of the vacuole. Explain. 
Draw a single filament seen from the side to show its 
structure, ends, etc. ; a single cell seen sidewise to show 
its contents, structure of wall, etc. ; the same cell seen 
from the end with contents in natural position ; another 
cell plasmolyzed. 

B. — Reproductive Condition. 

a. General appearance. — Can you, without using a mi- 
croscope, distinguish this condition in any way, 
as by difference in color of the mass, length of 
filament, position in aquarium, etc., from the veg- 
etative condition ? 



WATER SILK 57 

b. The structure of the fruiting filament. — Are there any 
noticeable changes in shape or size as compared 
with the vegetative filament ? In color ? Do the 
cells have the usual contents ? Can you find 
the chromatophores, nucleus, etc., in each cell of 
the fruiting filament ? Is starch present ? 

g. The position of the fruiting filaments. — In what posi- 
tion do the fruiting filaments lie? What deter- 
mines this position mathematically? Physiolog- 
ically ? Do the filaments touch at all points ? Do 
you find a filament in any part of its course in 
contact with more than one other filament ? 

d. The conjugating tubes — How many does each cell 

have ? Do all of the cells have them ? How do 
they compare in shape and size with the rest of 
the cell ? Look for tubes in various stages of de- 
velopment. How are they formed ? Are they a 
mere " bulging out " of the cell- wall, or are they 
true outgrowths of the same? Do they always 
grow from the same side of the cell? What is 
their structure ? Do they show the same struct- 
ure and composition as the cell-wall ? What de- 
termines their place of formation physiologically? 
Are the filaments actually in contact before the 
tubes form? Are they open at the outer end 
from the first stages of formation ? If not, when 
do they become open? Do the tubes in conju- 
gating filaments appear to be permanently grown 
together, or are they only in temporary contact ? 
What becomes of the tubes after the zygospore 
is formed? 

e. The zygospores. — Do they occur in both filaments % 



58 THE BIOLOGY OF THE CELL 

Are they formed in each cell of the fruiting fila- 
ment? What determines their place of forma- 
tion? Is there any visible difference, such as 
would indicate sex, between the two filaments 
whose cells conjugate to form the zygospores? 
Look for zygospores in various stages of develop- 
ment. Can you find the different stages of this 
process exhibited in a single filament ? What are 
the details of the process ? What is the shape of 
a ripe spore? Structure? What is left in the 
conjugating cells after the zygospore is formed ? 
What significance in the name " zygospore " ? 
Can the spore pass out of the cell through the 
conjugating tube ? If not, how can the spore get 
out ? After the formation of the spore is the cell 
living or dead ? Notice that the entire cell-con- 
tents which at one time is " vegetative " becomes 
" reproductive." 
Draw a number of cells to illustrate the facts 
learned. 

PHYSIOLOGY 

In addition to the physiological topics studied in the 
examination of the reproductive stage of the plant, the 
following may be investigated : 

A. — Formation of Starch {Assimilation). 

I. Effect of light. 

a. Take some filaments of Spirogyra whose cells are 
known to contain starch, place the filaments in a 
dish of water, and set the dish in a warm, dark 
place for two or three days, or until microscopic 
examination shows no starch to be present, being 
careful to prevent the total evaporation of the 



WATER SILK 59 

water in the dish. At the end of the time stated 
examine some of the filaments under the micro- 
scope, and note the changes in the chlorophyll 
bodies and starch grains. What has become of 
the starch ? 
b. Expose some of the filaments used in the preced- 
ing experiment to the bright sunlight for fifteen 
minutes to two or three hours according to the 
intensity of the light, then test with iodine. Is 
starch present? Explain. Note the bubbles of 
gas given off by plants exposed to the sunlight. 
Compare these with the plants growing in ponds. 
What causes the plants to float at the surface of 
the water when exposed to the sunlight ? What 
advantage in this ? Why do they sink down in 
the water at night ? What advantage in this ? 
Is it possible that the slimy excretion on the fila- 
ments may assist in any way to float the plant ? 
Why? 
What conclusions do you draw from these experi- 
ments ? 

II Effect of carbon dioxide. 

a. Boil some distilled water to drive off any carbon 
dioxide it may have absorbed, cool the water, 
place some of the filaments used in I. a. in a vial, 
fill the vial completely with the cooled water, 
and set it in the sunlight for fifteen minutes 
to an hour, then test for starch as in /. b. What 
results ? 

b. Take some more of the filaments used in L a., 
and put them in a vial of hydrant water, which 
usually contains carbon dioxide, and set the vial 
alongside of II. a. for the same time. Compare 



60 THE BIOLOGY OF THE CELL 

results. Does starch form more or less rapidly in 
this case than in II a. f 
"What conclusions do you draw from these two ex- 
periments ? 

B. — Growth. 

a. Put some filaments of Spirogyra into a bottle 

containing distilled water, and set the bottle in 

the sunlight. 
o. Put some filaments of Spirogyra into a bottle 

containing Sachs's food-solution for green plants. 

Let the two bottles stand in the sunlight for a 

week or two, then compare the results found in 

each experiment. In which bottle do the plants 

grow better ? Explain. 

C. — Cell-formation. 

a. Place some actively growing filaments of Spiro- 
gyra in a cold place (almost freezing) overnight. 
Examine them early next day for cells in the 
process of division. What are the first steps in 
the process? What changes take place in the 
nucleus ? In the chromatophores ? In the cell- 
wall? Is the process confined to any particular 
part of the filament ? To particular cells ? How 
long does it last ? Can you now account for the 
difference in thickness between the end and side 
walls ? Would you consider cell-formation to be 
a kind of reproduction ? Why ? In what re- 
spects is cell-formation in the plant different from 
spore-formation ? 
Make drawings showing the various stages of cell- 
formation seen. 

General Questions. — Is a filament of Spirogyra a sin- 



WATER SILK 61 

gle plant consisting of many similar cells, or a colony 
of unicellular plants ? Why ? What do you regard as 
the main points of difference between Spirogyra and 
jProtococcus considered both morphologically and phys- 
iologically ? Between yeast and Spirogyra ? 

Eeview all of your studies of animal and plant cells. 
Do you consider the cell to be an organized body ? If 
so, why ? 



Part II 
THE BIOLOGY OF THE ANIMAL 



THE BIOLOGY OF THE ANIMAL 



Sponges 
Example 1. — Skeleton of Toilet Sponge {Euspongia Sp.) 

Material. — Specimens may be obtained at any drug 
store. It must be borne in mind that these are almost 
invariably imperfect, since in preparing the sponge for 
market it is trimmed more or less to give it a symmet- 
rical shape. The trimming is usually confined to the 
base, which contains a collection of debris consisting of 
sand, small pebbles, pieces of shells, etc., whose presence 
would affect the market value of the sponge. Branched 
forms also are clipped to make them into a more conven- 
ient shape. Students will readily detect the places which 
have been trimmed by the fact that the surfaces are 
smooth and even. The small sponges used for washing 
slates are generally pieces sheared off larger sponges. 
It is well to have for comparison some fine surgeon's 
sponges as well as the coarser kinds used for washing 
carriages. 

Besides the specimens the student will need a mag- 
nifying - glass, compound microscope, scissors or sharp 
knife, and a tumbler of water. 

Method of Examination. — The sponge skeleton should 
5 



66 THE BIOLOGY OF THE ANIMAL 

first be examined entire, then with a sharp knife or 
scissors be cut into several sections parallel with the 
base ; a second specimen should be cut into vertical 
sections. Small scraps may be torn off the tips of the 
canals and examined under the low power of the mi- 
croscope. 

MOEPHOLOGY 

a. Shape. — Do you find that all of several specimens 

have the same general shape ? What is it ? Do 
you find any noticeable variations from this ? If 
so, can you suggest any reasons for such varia- 
tions? Can you readily detect an upper and a 
lower side of the sponge body ? How ? Eight 
and left ? How ? Notice the elevations of the 
general surface. Have they any relation to the 
large canals which run through the mass of 
the sponge skeleton % 

b. Size. — What is the average size of a number of speci- 

mens ? Do you consider this the average size at- 
tained by this kind of sponge, or is it merely the 
marketable size ? Why ? 

c. Color. — What is the usual color of a toilet sponge? 

It must be remembered that many sponges are 
bleached during the process of preparing them 
for market. Such sponges usually have a bright- 
yellowish tinge. 

d. Elasticity and porosity. — Squeeze a dry sponge tight- 

ly in the hand. Does the sponge regain its orig- 
inal size % Does it show any tendency to do so % 
Now put the same sponge into a dish of water 



SKELETON OF TOILET SPONGE 67 

and note the change. How do you account for 
it \ Is a wet sponge more elastic than a dry one? 
Soak a sponge thoroughly in water, then squeeze 
out as much as possible of the water into a dish 
and measure the amount. 

e. Structure, 

1. The oscula (large openings on the upper sur- 

face of the sponge). — How many on your spec- 
imen ? What is their shape ? Size % Note 
that each osculum is the outlet of a canal 
which runs down into the body of the sponge. 
Look down into an osculum and notice the 
numerous smaller canals which open into the 
large one. Notice also that the skeleton be- 
comes thinner and less compact at the margin 
of the osculum. 

2. The canals. — With a sharp knife or a pair of 

scissors cut through the skeleton so as to 
divide at least one of the large canals length- 
wise. How far into the body does the canal 
penetrate ? Does it decrease or increase in size 
as it approaches the osculum ? Do any of the 
large canals unite directly or are they connect- 
ed by smaller canals ? Do the walls of the 
canals have the same appearance as regards 
smoothness, texture, color, etc., as the surface 
of the skeleton % 
Make outline drawings showing the sponge as seen 
from the side and from the top, indicating the posi- 
tion of all of the large oscula ; also a drawing of a 
section showing the course of some of the principal 
canals. 

3. The fibres. — Look closely at the surface of the 



68 THE BIOLOGY OF THE ANIMAL 

sponge skeleton and notice that it is construct- 
ed of fibres united together. Can you detect 
with or without a magnifying - glass whether 
these fibres differ in size, color, arrangement, 
etc., in different parts of the skeleton ? If you 
find any differences, how do you account for 
them? Tear off a small scrap of the skeleton 
and examine under the low power of the com- 
pound microscope. What arrangement of the 
fibres do you find? Does this give you any 
clew to the reason why a toilet sponge can 
absorb so much water? Look again for dif- 
ferences in the shape and size of fibres. How 
are the fibres held together ? Do you find any 
traces of joints ? Do you find any foreign 
bodies, as grains of sand or pieces of shell 
firmly attached to the fibres or incorporated 
in them ? If so, how do you account for their 
presence ? 
Draw a magnified piece of sponge to show the shape 
and arrangement of the fibres. 

Example 2.— Fresh-water Sponge (Spongilla Sp.) 

Material. — This sponge is common in many lakes 
and rivers throughout the country. It forms dark- 
green patches on the surfaces of submerged rocks, 
logs, pieces of bark, etc. It frequently grows in 
large, branched clusters from a few inches to a foot 
or more in length, the branches sometimes being as 
large around as the thumb. Owing to the color and 
shape of these branched forms they are often mis- 
taken for water -weeds or masses of algae. The dif- 
ference can be told at once even by an inexperienced 



FRESH- WATER SPONGE 69 

person, for, if a piece of sponge be gently pressed be- 
tween the thumb and finger, it crumbles to fine par- 
ticles which feel gritty. Further, a close examina- 
tion, with or without a hand -lens, will show numer- 
ous fine openings scattered over the surface if the 
specimen really be a sponge. In collecting Spongilla 
put the specimen together with the object to which 
it is attached into a pail with an abundance of water, 
and handle as little and as gently as possible. By 
changing the water three or four times a day speci- 
mens may be kept alive for several days. A good plan 
is to set the pail where a slow stream of water may 
flow through it. The following are especially good 
places to find specimens ; the rocks at the foot of a 
mill-dam, the sluice-ways and gates of a mill, and the 
under side of rocks and logs in swift-flowing streams. 
There is almost always a possibility of finding them in 
clear, rapid streams, but never in water which is per- 
manently muddy. The best specimens are to be found 
between July and December. 

To prepare alcoholic specimens for preservation drop 
pieces of the branches of the living Sjpongilla into about 
fifteen or more times their bulk of absolute alcohol and 
change the alcohol at the end of two or three hours. 
The color of the specimen is altered, but the structure 
is well retained. 

In the examination will be used the hand-lens, com- 
pound microscope, acetic acid carmine, hydrochloric 
acid, fine bristles, chalk or indigo, and forceps. 

Method of Examination. — Living Spongilla should be 
examined where found if practicable. If removed to 
the laboratory the examination should be made at the 
earliest possible moment, as it is very difficult to keep 



70 THE BIOLOGY OF THE ANIMAL 

specimens alive. Alcoholic material may, without seri- 
ous injury, be transferred to a dish of fifty per cent, 
alcohol, but should not remain more than an hour or 
two, otherwise maceration will take place. 



MORPHOLOGY 

a. Shape. — What is the shape of the branched form? 
Does it have a single trunk? How many 
branches has it ? Does each branch remain sep- 
arate — i. <?., not connected to others — throughout 
its course? If not, how are the branches con- 
nected? What is the shape of the specimen at 
the point where it is attached to its support? 
Does it have any root-like outgrowths? What 
shape as regards outline and thickness do the 
flat forms of Spongilla take ? 
Sketch several specimens in outline. 

h. Size. — How high is your specimen ? What is its ex- 
treme width between the tips of the branches ? 
If a main trunk is present, how long is it ? What 
is its diameter ? What are the length and diam- 
eter of the longest branch? Of the shortest? 
Compare several specimens with respect to the 
features mentioned above. 

c. Color. — What is the color of Spongilla ? Is it a color 
common to animals? Compare several speci- 
mens to note variations in the color of the entire 
body and in its various parts. Where is the pre- 
vailing color most intense ? How do you explain 
this fact? Can you suggest any use for this 
particular color ? 



FRESH- WATER SPONGE 71 

d. Structure. 

1. The body-substance or " flesh." — With the 

unaided eye or with a hand-lens what can you 
make out with regard to the substance of 
which the body is composed — its color, con- 
sistence, etc. \ Is the surface of the body 
smooth, or does it present elevations ? If the 
latter, are there places where the elevations 
are more numerous than elsewhere ? Note the 
arrangement, shape, and size of the openings or 
pores scattered over the surface of the body. 
What relations exist between the pores and 
the elevations, if any of the latter are found ? 
Explain reasons for same. 

2. The microscopic structure. — With fine for- 

ceps carefully tear off a small portion of the 
body-substance, mount it in a drop of water, 
and examine under the low power. Note the 
body-substance. Is it granular or homogene- 
ous? If the former, of what do the granules 
consist ? What is their color ? Note the trans- 
parent, pointed bodies or spicules embedded 
in the body-substance. Do they have a definite 
arrangement? Are they numerous or few? 
Are they evenly scattered through the body % 
What is their shape? Do you find any 
parts corresponding to the fibres of the toilet 
sponge ? 

Put on the high power and look for isolated 
cells which have been separated from the frag- 
ment of the body. How many kinds of cell 
do you find? Are any of them amoeboid in 
shape ? Any flagellate ? Do they remind you 
of any Protozoa you have seen ? Are the cells 



iV THE BIOLOGY OF THE ANIMAL 

closely joined together as in a membranous 
tissue, or do they readily separate from one 
another? What do they contain? Do you 
find that the cells bear any definite relation to 
the spicules? Examine some of the spicules 
more carefully, and note the dark line (cavity?) 
running through the middle. Eun a drop of 
acetic acid carmine under the cover -glass. 
What changes take place in the cells ? In the 
spicules ? Can you find nuclei in the former ? 
Mount a fresh preparation and run a drop of 
hydrochloric acid under the cover-glass. What 
effect has the acid on the spicules? If the 
spicules dissolve, forming bubbles, they are 
composed of carbonate of lime, the bubbles 
being carbon dioxide ; if the spicules remain 
undissolved they are composed of flint, this 
substance and carbonate of lime being the ma- 
terials of which the spicules of various sponges 
consist. 

Look for the statoblasts, amphidiscs, or 
gemmules, yellowish toothed disks connected 
by a rod-shaped piece, which are formed in the 
autumn and serve to reproduce the sponge in 
the following spring. 

PHYSIOLOGY 

a. Movements. — Can you tell from watching the living 
Spongilla, and noting especially its mode of at- 
tachment, whether or not it can move from place 
to place ? How does it compare in this respect 
with the toilet sponge, judging entirely by what 
vou have observed in the structure of the latter ? 



GKANTIA 73 

Can you decide whether or not the branches of 
Spongilla move ? With a very fine bristle care- 
fully touch the surface of the body-substance, 
several times if necessary, in the neighborhood 
of an osculum. Do you detect any change in 
the latter % Does it open wider or close % Can 
Spongilla feel ? 

Put a fragment of the body-substance of living 
Spongilla under the microscope, and note the 
motions of the amoeboid and flagellate cells. 

b. Ingestion. — Sift some particles of finely powdered 
chalk, indigo, or carmine into the water contain- 
ing living Spongilla, and look through the water 
towards the light to see whether the particles 
are drawn into the oscula or washed away from 
them? Can you from your own observations 
explain why the current of water flows in this 
direction ? What, then, seems to be the function 
of the oscula ? 

General Questions. — Is there anything about the 
structure or mode of life of Spongilla which would lead 
you to suppose that it might be used as food or de- 
stroyed in other ways by water animals ? If so, has it 
any means of protection against them ? By what means 
may it be distributed through lakes and rivers ? 



Example 3.— Grantia (Sp.) 

Material. — Students living along the New England 
coast can obtain this sponge in the living condition, in 
which case some points in its physiology may be studied 
as indicated for Spongilla. It is especially valuable, 



74 THE BIOLOGY OF THE ANIMAL 

however, on account of the simplicity of its structure. 
The following study is based upon alcoholic material, 
which the student may prepare for himself or may ob- 
tain from sources mentioned in the introduction. Speci- 
mens of two kinds may be prepared, the first to retain 
the spicules, the second to be decalcified so that the tis- 
sues may be examined. The first kind of specimens may 
be dried, or may, while still living, be placed into seven- 
ty-five per cent, alcohol, where they should remain for a 
day, then they may be transferred to ninety per cent, 
alcohol and left until needed for examination. In each 
case the bulk of the alcohol should be several times that 
of the specimens. Decalcified specimens may be pre- 
pared by placing either living or alcoholic sponges into 
one per cent, to two per cent, solution of chromic acid 
for twenty-four to thirty-six hours, during which time 
the acid removes the spicules by dissolving them, but 
hardens and preserves the cellular tissues. The decalci- 
fied sponges are then to be passed through the various 
grades of alcohol, being left in the strongest until it is 
no longer discolored by the acid, embedded in celloidin 
or parafiBne, and sectioned free-hand with the razor or, 
better, on the microtome. 

Other material required : Delafield's hsematoxylin, 
borax carmine, or acetic acid carmine, fifty per cent, 
glycerine or Canada balsam, watch-glass, test-tube, alco- 
hol lamp, pipette, potash, compound microscope, and hy- 
drochloric acid. 

Method of Examination. — Study first, with or with- 
out the hand-lens, the entire specimen in the living state 
if obtainable; if not, alcoholic material may be used, 
the specimen being kept in a watch-glass or small dish 
containing fifty per cent, alcohol. Other specimens, 



G-RANTIA 75 

preferably alcoholic, as these are tougher, should be di- 
vided into halves longitudinally with the razor, and 
still others cut transversely. If the conveniences neces- 
sary for celloidin or paraffine embedding and the micro- 
tome are not at hand, fair sections may, after a little 
practice, be made with the razor from well - hardened 
alcoholic material. Such sections may be stained in 
Delafield's hematoxylin, borax carmine, or, if decalci- 
fied, in acetic acid carmine, and then mounted in water, 
fifty per cent, glycerine, or Canada balsam after passing 
through the preliminary treatment required by the dif- 
ferent fluids. 

Spicules may be isolated for examination free from 
the tissues, by placing specimens in a test-tube or watch- 
glass containing potash, boiling for a few minutes, dur- 
ing which the fleshy parts of the body dissolve, allowing 
the sediment to settle, pouring off the fluid, and rinsing 
the sediment several times with fresh water, being care- 
ful each time to allow the sediment to settle before pour- 
ing off the water. A drop of the sediment may then be 
taken out of the test-tube with a pipette and placed on 
the slide for examination. 

MORPHOLOGY 

With an entire specimen notice : 

a. Shape. — What is the usual shape of a single sponge ? 
Is it a symmetrical form ? Can you distinguish 
an upper and a lower end ? How ? Is the sponge 
attached to anything, or is it free to move about? 
If the former, to what is it attached? Is its shape 
at all modified for this purpose ? Do you find any 
decided variations from the general shape ? Can 
you explain them ? Are all of your specimens 



76 THE BIOLOGY OF THE ANIMAL 

single individuals, or do you find evidences of 
budding? If the latter, from what part of the 
parent sponge does the bud grow ? Does it differ 
much from the parent in shape ? 
Make enlarged drawings of single and of budded 
specimens. 

b. Size. — What are the length and diameter of your 

largest specimen ? Of your smallest ? How 
many different sizes of the bud do you find? 
Have you any specimens which, as regards size, 
are of commercial value ? 

c. Color. — "What is the color of the living sponge ? Of 

the alcoholic specimen ? Compare with Spongilla. 
Has your specimen the same color as the object 
to which it is attached ? 

d. Structure. 

1. The osculum or excurrent opening. — Where is 

it ? Do you find more than one on an individ- 
ual sponge ? How does its diameter compare 
with that of the body ? Notice the cluster of 
spicules around the osculum. How are they 
arranged? Do any of the buds have oscula? 
Does each have an osculum? 

2. The body- cavity, gastral cavity, or cloaca. 

— In a specimen without buds, which has been 
halved lengthwise, note the body -cavity ex- 
tending downward from the osculum. What 
is the shape of the -cavity ? How far into the 
mass of the sponge-body does it extend? Do 
you find any variations in its diameter ? How 
does its diameter compare with the thickness of 
the body-wall? Do you find that the body- 



GKANTIA 77 

cavity has branches? Make a longitudinal sec- 
tion through the middle of a budded specimen, 
and note whether a branch of the body-cavity 
of the parent extends into the bud. 

3. The body- wall. — Examine the longitudinal 

sections with a low power. Note the spicules 
covering the surface of the sponge, also the 
whitish sponge flesh, and on the cut surface of 
the section the longitudinal (radial) canals or 
incurrent openings running through the wall 
from the surface toward the cloaca. Are these 
canals numerous? What is their shape as seen 
lengthwise and endwise? How are the outer 
ends of these canals guarded? Are the inner 
ends likewise protected? Why? Notice the 
mass of debris among the spicules which cover 
the surface of the body. In what ways do the 
flesh and spicules of the bud differ from those 
of the parent ? Examine transverse sections of 
the sponge. Do you find that the body-wall 
projects into the body-cavity in such a way as 
to subdivide the latter into smaller cavities? 
Or is it a single continuous cavity ? 

4. The spicules. — Prepare some spicules as di- 

rected, and examine under the low power. 
How many shapes do you find? Draw each 
kind. Compare with the longitudinal section 
of the sponge, and note in what part of the 
body each kind of spicule is found. What is 
the shape of the spicules found on the surface 
of the sponge? Of those embedded in the 
flesh ? Can you suggest any reasons for these 
shapes ? Put a drop of hydrochloric acid upon 
some of the isolated spicules. What is the re- 



78 THE BIOLOGY OF THE ANIMAL 

suit ? Compare with the same experiment on 
the spicules of Spongilla. What difference? 
Of what are the spicules of Grantia composed ? 
5. The histological structure. — Good results can 
usually be obtained only from material which 
has been stained — e. g., in Delafield's hematoxy- 
lin, eosin, or borax carmine — embedded in cel- 
loidin or paraffine, and sectioned preferably on 
a microtome. If such sections can be obtained, 
the more minute structure of the sponge may 
be studied under the high power. It will then 
be seen that the sponge flesh or syncytium, 
which fills all the space among the radial 
canals and in which the spicules are embed- 
ded, is made up of granular protoplasm in 
which many nuclei are prominent. Sometimes 
the outlines of the constituent cells may be dis- 
tinguished. The radial canals are lined with a 
layer of cells which form the endoderm. Pos- 
sibly, in well-prepared specimens, each cell of 
the endoderm may be seen to have a single 
long cilium or flagellum. In places may be 
found dark -colored oval or spherical masses, 
eggs or embryos, lying in the syncytium just 
below the endoderm. 

An excellent method of obtaining isolated sponge cells 
for microscopic examination is to put living sponges, as 
Grantia, Chalinula, etc., into a dish of sea water, quiet- 
ly remove nearly all of the water with a pipette, then 
quickly pour over them a saturated solution of corrosive 
sublimate. After a moment the water in the neighbor- 
hood of the sponge, especially if carefully agitated, will 
become milky. Put some of this cloudy water on the 



GKANTIA 19 

slide and examine with a high power. Note the great 
number of amoeboid cells with their processes, of sin- 
gle and clustered flagellate cells, of spicules embedded 
in amoeboid cells, of diatoms and other foreign bodies 
which wash out of the sponge body. 

Run a drop of Delafield's haematoxylin under the 
cover -glass and note the distinctness with which the 
nuclei of various cells are brought out, also the collars 
and flagella of cells from the endoderm. Compare these 
cells with the ciliated cells examined on page 26. 

Look for amoeboid cells which have ingested diatoms, 
plant-spores, etc. 



Fresh-water Polyp {Hydra Sp.) 

Material. — It is seldom that one is so situated as to 
have a supply of living hydras at hand whenever he 
wishes, as they are very unreliable animals in their 
habits ; they may be found in great abundance one 
year and not at all the next. Very little can be given 
in the way of definite directions for obtaining living 
specimens, and, owing to the difficulty of killing them in 
the expanded state, those preserved in alcohol are usu- 
ally so shrunken as seldom to be suitable for beginners 
to study. Perhaps the best method of obtaining mate- 
rial is to get from stagnant ponds or marshy lakes a good 
supply of submerged or floating water weeds, for exam- 
ple Elodea Canadensis and duck-weed (Zemna), put that 
gathered at different places into separate glass jars, with 
a label on each to indicate the locality whence the ma- 
terial came, and set the jars filled with clear, fresh wa- 
ter on a table near a window, but not exposed to the 
direct sunlight. In the course of a few hours carefully 
examine the lighted side of each jar for hydras. Hav- 
ing learned in this manner that specimens are to be 
found in a certain locality, further supplies of water 
weeds may be gathered. If the number of specimens 
found should not be sufficiently large to supply the 
class, work on this form may be delayed until addi- 
tional specimens can be raised. This may easily be 



FRESH- WATER POLYP 81 

done by keeping the jars exposed to diffused light in 
a warm room, and supplied with water plants and small 
fresh-water crustaceans, as Daphnia, Oypris, etc. It 
may be well to keep the jars covered to prevent evapo- 
ration and the access oi dust. From time to time the 
jars may be set in the sunlight, in which case it is best 
to darken the lower one-third of each jar by wrapping 
it in a dark cloth or setting it in a close-fitting paste- 
board ring made from a hat -box. In this way over 
three hundred hydras were once raised during one win- 
ter in a jar which in the previous autumn was known 
to contain only about twenty specimens. Bits of raw 
meat, hand-lens, dissecting needles, bristle, wire, tum- 
bler, dilute acetic acid, and compound microscope will 
also be required. 

Method of Examination. — Specimens are very likely 
to be found on the lighted side of jars which have stood 
near a window for some hours. Without disturbing the 
jars in the least first examine the animals without and 
with a hand -lens, noting as many as possible of the 
characters given on the following pages; then, if the 
hydra is attached to the side of the jar, by means of a 
pipette suck the animal loose from its point of attach- 
ment, previously loosening its attachment with a cam- 
eFs-hair brush, or, if fastened to a root of water plant, 
snip of! the root with a pair of fine scissors, transfer 
with enough water to cover well to a watch-glass or a 
concave slide in which the specimen may again be ex- 
amined with the lens. If light-colored, the animal may 
be made more plainly visible by placing the watch- 
glass on a dark background, as a black book or dark 
paper, or, if dark-colored, vice versa. Later, place the 
watch-glass upon the stage of the microscope, and 
6 



82 THE BIOLOGY OF THE ANIMAL 

study both in direct and in reflected light with the low 
power. 

MORPHOLOGY 

a. Size. — Is the animal plainly visible ? Do its length 
and breadth vary at different times ? Is there 
any relation between the variations in the two 
dimensions ? Does the size of the attached por- 
tion or disk vary ? 

h. Shape. — What is the general shape of the body? 
Does the body keep a definite shape ? Is it 
symmetrical ? Is the body flexible or rigid ? 
Do you find any specimens whose bodies are 
plainly irregular in shape? Are these irregu- 
larities the same in position and size on differ- 
ent individuals ? Do you find any specimens 
which appear to be colonies rather than single 
individuals? If so, of how many individuals 
does the colony consist? Are all the members 
of the colony equally well developed ? At what 
points are their bodies united ? 

c. Color. — What is the general color of the body? 

Does it vary in different individuals? Is the 
body of the same individual evenly colored ? 
Does its color vary at different times ? 

d. Structure. — Make out the following parts of the 

body: 
1. The disk or foot (attached portion). — How 
much of the entire body does it form ? How 
does it compare in diameter with the body 
proper? What is its outline? Is the body 
attached by any other part than by its base ? 



FRESH- WATEK POLYP 83 

2. The body proper. — What is its shape? Does 

the shape change? Is its diameter uniform 
throughout? Compare the color of this part 
with that of the disk. Can you discover a cav- 
ity or enteron inside the body-wall ? Note the 
mouth at the upper end (hypostome) of the 
body proper. What is the position of the mouth 
with regard to the tentacles ? Endeavor to find 
a specimen tying with the mouth directed tow- 
ards you, so as to see its shape and size. 

3. The tentacles. — What is their position on the 

body ? How are they arranged ? How many 
can you find ? Is their number invariable on 
different specimens ? Are the tentacles of the 
same size ? Do they ever vary individually or 
collectively in this respect ? If both the brown 
and green species of Hydra are available, com- 
pare the tentacles as to number and variability 
in both forms. 
Make drawings illustrating all of the structures stud- 
ied thus far. 

PHYSIOLOGY 

a. Movements. 

1. Contractility. — What various motions can you 

detect in the body proper ? In the tentacles ? 
Do either the tentacles or the body change in 
shape, size, or color as they move? Are the 
movements of the various parts at all uniform 
or rhythmic in character ? 

2. Locomotion. — Examine a jar of hydras, for some 

time if necessary, to see whether or not you 
can find any of them moving about. If not, 
with a pen or with a pencil which will mark on 
glass or with a fine camel's-hair brush put a 



84 THE BIOLOGY OF THE ANIMAL 

small dot on the surface of the glass jar so as 
to cover the point of attachment of each of sev- 
eral hydras. Leave the jar undisturbed for a 
time, then look to see if any of the animals 
have changed or are changing position. If not, 
quietly turn the jar a little, so that the light 
may strike it from a slightly different direc- 
tion, and examine again after a time. Have 
any of the hydras moved? If so, in what di- 
rection ? Do all move ? Do they migrate at 
the same time ? At the same rate ? To the 
same distance from the original position ? In- 
dicate the new position by a new set of marks, 
as by circles or dashes, endeavoring to trace 
the path of each animal. Turn the jar again 
and repeat the examination. If the student 
has time and inclination, let him watch to see 
the manner in which the hydra moves from 
place to place. Does it use the foot alone? 
How rapid is its progression ? 

If the above experiment prove successful, 
what would you say has caused the hydra to 
change place ? 

The following method may also be tried to 
induce the hydras to move : With a fine thread 
suspend a small piece (about one-eighth of an 
inch square) of raw beef against the inside of 
the jar of water in which the hydras are kept. 
If possible, hang the meat in the midst of a 
group of the animals in such a position that 
the meat will be an inch or more distant from 
each hydra. Does the meat prove attractive ? 
If so, which animals move first, those above, 
beloAV, or at one side of the meat ? 



FRESH-WATER POLYP 85 

Lay a wire across the top of the jar, and 
from the wire suspend by means of a thread 
a second scrap of meat out in the water a dis- 
tance of an inch or two from the side of the 
jar and near another group of hydras. Do any 
of the hydras get out to the meat ? If so, how ? 
Judging from these experiments, what methods 
of locomotion would you ascribe to the hydra ? 

b. Nutrition. — Put a few scraps of raw beef about as 

large as the head of a pin into a watch-glass con- 
taining two or three hydras, and watch with the 
low power or with a hand-lens to see the behav- 
ior of the animals. In what way do they seize 
the meat? How is it conveyed to the mouth? 
How swallowed? With the hand-lens carefully 
examine a number of specimens attached to the 
inside of the glass jar to see whether or not you 
can find any which have caught any of the water 
fleas or other small crustaceans which were put 
in with the hydras. How does the hydra behave 
when any of the crustaceans come in contact 
with it? What apparently happens to the crus- 
tacean ? Look for hydras which have swallowed 
small water animals, and note their position and 
condition in the body of the hydra. 

c. Nervous Properties. 

1. Irritability. — Is the hydra disturbed when irri- 
tated by coming in contact with a foreign 
body, as when gently touched once with a fine 
bristle ? What does the animal do under such 
circumstances ? What is its behavior upon be- 
ing touched repeatedly ? 



86 THE BIOLOGY OF THE ANIMAL 

2. Influence of light (heliotrqpism). — Put several 

hydras into a beaker or a tumbler, give them 
time to become fixed in position, mark on the 
glass the position of each individual, then 
cover the top and sides of the beaker with 
thick opaque paper or cloth. At one side 
make a hole about one-half inch in diameter 
through the paper to the glass, so as to admit 
the light. Set the beaker in a well -lighted 
place, but not in direct sunlight, and examine 
after a few hours' exposure. Have the hydras 
changed their positions ? If so, what relation 
does their present position bear to that of the 
hole in the paper % Are hydras sensitive to a 
small amount of light ? 

3. Co-ordination. — Do the movements of the hydra 

seem to be made at random or for a purpose ? 
Do any of your observations lead you to think 
that the animal performs intelligent actions ? 

Microscopic Structure. — Put on the high power and re- 
view all of the doubtful points of morphology 
and physiology, and in addition investigate the 
following topics : Is the stomach cavity or en- 
teron continuous throughout the body proper % 
Can you discover an intestine ? Does the enteron 
extend into the tentacles ? Is there an opening 
in the foot ? Can you find any opening, the 
anus, through which waste matter may leave 
the body ? Study the structure of the body-wall, 
and note the two cell-layers, the outer or ecto- 
derm and the inner or entoderm, and between 
the two the supporting layer or mesoglcea. 
Does the ectoderm cover the entire surface of the 



FEESH-WATEE POLYP 87 

body, including the tentacles ? How much of the 
thickness of the body- wall does this layer form ? 
What are the shape, relative size, color, and ar- 
rangement of the cells in this layer? Examine 
both extended and contracted specimens with re- 
gard to the points last mentioned. Scattered 
among the ectoderm cells on the tentacles, no- 
tice the " thread cells " or cnidoblasts, in which 
lie highly refractive capsules, the neniatocysts, 
each enclosing a spirally-coiled thread, and the 
outer end of which terminates in a sharp spine, 
the cnidocil. On what part of the tentacle are 
the nematocysts most abundant ? Are they regu- 
larly arranged? Do you find any on the body 
proper ? On the hypostome ? How do they com- 
pare in shape and size with the ordinary ectoder- 
mal cells? Notice that, in addition to the two 
kinds of cells already studied, the ectoderm also 
contains among the bases of the larger cells small 
or interstitial cells. Compare these with the 
others. 

Does the entoderm line the entire body-cavity ? 
Does it extend into the tentacles? How does it 
compare with the ectoderm in thickness ? Are its 
cells larger or smaller than those of the ectoderm ? 
What is their shape ? Color ? To what is the 
color due? Can you see a circulation of food- 
particles in the body-cavity ? In the tentacles ? 
Can you detect the cause of this circulation ? Do 
any of the entodermal cells bear cilia or flagella? 
What changes take place in the entoderm when the 
animal contracts ? How thick is the supporting 
layer ? Can you trace it throughout the body ? Can 
you discover whether or not it is composed of cells? 



88 THE BIOLOGY OF THE ANIMAL 

Draw a portion of the body- wall, showing the arrange- 
ment of the cell -layers and the shape and position of 
the constituent cells. 

Can you detect the presence of eyes or of any organs 
by which the hydra can perceive light ? Do you find 
any nerves or muscles 1 Brain ? Do you find organs 
of any kind inside the body ? After the foregoing top- 
ics have been studied, run a drop of dilute acetic acid 
under the cover-glass. What change takes place in the 
position of the body and tentacles ? "What happens to 
the nematocysts? Notice the shape and length of the 
threads. Of what use to the animal can be this be- 
havior of the nematocysts ? 

From a well-fed community of hydras select an indi- 
vidual which bears buds, and in addition to the topics 
studied before, investigate the following : Does the en- 
teron of the parent extend into the bud ? Do the cell- 
layers do the same ? Do all of the buds have tentacles ? 
Up to what point in their development do the buds re- 
main attached to the parent ? To what extent and for 
how long is the bud dependent upon the parent for food- 
supply ? Do you find any buds which are just about to 
leave the parent? How do you distinguish them ? What 
appear to be the first steps in the formation of a bud? 

Make sketches showing the manner in which the bud 
is attached to the parent, buds in various stages of de- 
velopment, and the relation of the enteron and cell-lay- 
ers of the bud to those of the parent. 

Examine mature individuals for the presence of sex- 
ual glands (testes and ovaries), both of which may be 
found on the same animal, the former as small, knob- 
like swellings near the tentacles, the latter as larger 
spherical swellings farther down on the body. How 
many testes do you find on one individual? Is the 



FKESH- WATER POLYP »y 

number constant ? In which layer and from which 
cells do the testes develop ? Compare the ovaries with 
the testes. Can you find the ovum itself? Press the 
cover-glass so as to crush the testes, and note the 
spermatozoa. What is their shape ? Size ? Are they 
motile or motionless? 

Draw a specimen in which these organs are visible. 

An excellent method of preparing isolated cells of the 
ectoderm and entoderm for study is to put a hydra into 
Miiller's fluid for a day, then with fine dissecting nee- 
dles carefully tease it to pieces in fifty per cent, glyce- 
rine, and examine under high power. Prepared sections 
of the body may be made according to the directions 
given in the revised edition of Huxley and Martin's 
" Practical Biology." 



Campanularian Hydroid {Campanularia Sp.) 

Material. — The student should examine both living 
and alcoholic specimens. The former, however, can be 
obtained only by students who live not more than a 
day's journey from the coast. Pieces of rock-weed, 
various sea-weeds, eel-grass, bark, shells, etc., bearing 
specimens may be packed for shipment in a ventilated 
box with plenty of damp sea-weed. On arrival at their 
destination the specimens should be placed at once in 
carefully prepared artificial sea-water or in well-aerated 
natural sea-water, which may be shipped in casks. The 
hydroids may be kept alive long enough to give the 
student some idea of their appearance and motions. 

The structure is best studied in preserved specimens, 
and these are made by plunging as quickly as possible, 
so as to avoid contraction of the tentacles, the living 
hydroids into Perenyi's fluid, and leaving them for 
three to four hours, or in Kleinenberg's picro-sulphuric 
acid for the same length of time, then placing them 
in seventy per cent, alcohol for about twelve hours, 
and in eighty-five per cent, and ninety -five per cent, al- 
cohol, each for the same length of time. Some of the 
preserved material should be stained in hematoxylin, 
borax carmine, alcoholic carminic acid, etc., and mount- 
ed in Canada balsam. The rest may be left unstained 
and used for both macroscopic and microscopic exam- 
ination. 



CAMPANULAKIAN HTDROID 91 

The free - swimming medusoid forms are obtained 
by skimming the surface of the water on warm, still 
nights with a net of bolting-cloth (for full directions 
see Brooks's " Invertebrate Zoology "). The specimens 
thus caught may be killed in good condition by a short 
immersion in one-tenth per cent, osmic acid. Then 
transfer to a watch-glass of thirty per cent, alcohol, 
and finish the hardening in stronger grades made by 
adding to that in the watch-glass a few drops of ninety- 
five per cent, alcohol every few minutes. 

Method of Examination. — Living specimens free 
from foreign bodies, algae, mud, etc., may be examined 
in a watch-glass of sea-water. Study alcoholic material 
in a watch-glass of fifty per cent, alcohol. Specimens 
mounted in Canada balsam are, of course, "permanent 
mounts," and are ready for microscopic study at any 
time. 

MOEPHOLOGY 

Examine a cluster of the animals in a watch-glass 
filled with fifty per cent, alcohol and note the plant- 
like aspect of the cluster. Note also the root-like at- 
tached end or hydrorhiza, the main stalk or hydro- 
caulus with its branches, and the position of the zobids 
or hydranths on the branches. Then examine both 
living and prepared specimens, first with a low, then 
with a high power. 

a. General Form and Structure. — What is the general 
shape ? How do you distinguish the base of the 
specimen ? Is the cluster a colony of animals or 
a single animal? How are the branches ar- 
ranged on the main stem? Are there any dif- 



92 THE BIOLOGY OF THE ANIMAL 

ferences among the buds or zooids occupying 
the branches ? How many kinds are distinguish- 
able? Is the transparent covering or perisarc 
continuous over the entire cluster ? Is the fleshy 
part or ccenosarc continuous ? 

b. The perisarc. — Of what does it appear to be com- 

posed? What is its color? Does it vary in 
thickness in different parts of the cluster? Ex- 
plain. Note the annulations at the bases of the 
branches. Do these annulations occur anywhere 
else? What is the usual number of annulations 
on a branch ? 

c. The ccenosarc. — Where is it most plainly seen ? Is 

it attached to the perisarc at all points ? Is it 
everywhere covered by the perisarc ? Note that 
it is composed of two distinct layers of cells, the 
ectoderm or outside layer, and the entoderm or 
inside layer. How do these compare in thick- 
ness ? In color ? How are they connected ? Do 
you notice an}^ differences between the cells com- 
posing each layer? Can you detect a third or 
supporting layer lying between the other two ? 
How do you distinguish it from them? Are 
these layers traceable everywhere in the cceno- 
sarc? Compare with Hydra. Notice that 
through the centre of the ccenosarc runs a 
tube or body-cavity. Can you trace this tube 
throughout the entire colony ? 

d. The zooids. — Endeavor to find the kinds men- 

tioned below : 
1. The feeding zooids or hydranths. — What is their 
position in the cluster? Their shape? Are 



CAMPANULARIAN HYDEOID 93 

they entirely covered by the perisarc ? What 
is the shape of that portion (hydrotheca) of the 
perisarc which covers the body of the zooid? 
Note the tentacles. How many has each hy- 
dranth ? What is their shape ? Of what are 
they composed ? How are they arranged ? 
Note the groups of nematocysts or "lasso- 
cells" on the tentacles. How are they ar- 
ranged ? Are the tentacles flexible or rigid ? 
If living hydroids can be obtained isolate some 
of the nematocysts by crushing a tentacle un- 
der the cover-glass, and note their structure. 
Compare with Hydra. Examine also the 
mouth at the outer end, or manubrmm, of the 
body proper. Compare several zooids to see 
if the manubrium is flexible and the mouth 
distensible. What is its structure? Does it 
bear tentacles ? Examine the body of the hy- 
dranth. What is its shape? Of what is it 
composed ? What is the shape of the body 
or digestive cavity? Is the body-cavity a 
closed cavity ? How far does it extend into 
the tentacles? Do you ever in preserved spec- 
imens find in this cavity small molluscs, crus- 
taceans, etc., which have been captured for 
food ? How does a hydranth compare in struct- 
ure with a hydra ? 
Make an enlarged drawing of a single hydranth 
with its stalk, showing all of the structures visible. 

2. The reproductive zooids. — Position ? Shape ? 
Are they covered by the perisarc? Compare 
the shape of this portion (gonangium) of the 
perisarc with a hydrotheca. Do they have ten- 
tacles ? How do these zooids differ in internal 



94 THE BIOLOGY OF THE ANIMAL 

structure from the feeding zooids? Do you 
find coenosare, manubrium, digestive cavity, 
etc. % Examine the medusae in the reproductive 
buds, and note their attachment to the central 
stalk or blastostyle, which morphologically 
represents a rudimentary hydranth. Of what 
is the blastostyle composed? How are the 
medusae attached to it % How many medusae 
in each gonangium ? How do those in the same 
gonangium differ from one another ? How do 
you account for these differences ? 
Draw a reproductive zoo id showing medusae in va- 
rious stages of development. 

3. The young zooids. — Note their position, shape, 
and structure. Look for them in different 
stages of development. Can you distinguish a 
young feeding zoo id from a young reproduc- 
tive zooid ? Compare these young zooids as to 
position in the colony, shape, structure, etc., 
with the buds on a hydra. 
Draw young zooids to show the various stages in their 
growth. 

PHYSIOLOGY 

If living hydroids are obtainable the following topics 
may be studied. Many of the questions, however, may 
be satisfactorily answered by a careful comparison of 
the shapes, positions, contents, etc., of dead specimens. 

a. Movements. — Does the colony as a whole sway back 
and forth on the hydrocaulus? Is the hydro- 
caulus flexible enough to be bent by currents in 
the water ? Can you determine whether or not 
the colony can loosen the hydrorhiza from its 



CAMPANULARIAN HYDEOID 95 

base of support and migrate to another place? 
Can the branches bend ? What movements have 
the bodies of individual zooids ? Do the feeding 
zooids have more or less mobility than the repro- 
ductive and young zooids ? Why ? In what 
various ways do the tentacles move ? Does the 
ccenosarc in the branches move at all ? 

b. Feeding. — Feed a colony with very small scraps of 

meat placed in a watch-glass of sea-water, or, 
better, watch the capture of small animals swim- 
ming about the colony, and compare in all re- 
spects with Hydra. How do the tentacles be- 
have? Are the nematocysts used in this process? 
How is the food swallowed? Examine a liv- 
ing zooid under the high power, and endeavor to 
see the circulation of currents of fluid bearing 
particles of food through the body-cavity. Can 
you detect on the cells of the entoderm the cilia 
whose motions cause these currents ? Do the cur- 
rents flow through the branches and into the re- 
productive and the young zooids ? Why ? To 
what does this correspond in our own bodies ? 

c. Sensation. — While watching a colony in which the 

zooids are expanded, gently disturb the water 
in the watch-glass. Are the zooids disturbed? 
How do you tell? Carefully touch a single ex- 
panded zooid with a fine bristle. What does the 
zooid do? Are the neighboring zooids which 
were not touched disturbed ? If so, what prop- 
erty does this show the colony to possess ? 

General Questions. — Do you find any distinction be- 



96 THE BIOLOGY OF THE ANIMAL 

tween " body-cavity," in which various internal organs 
might be contained, and the "digestive cavity" in a 
zooid ? If not, would you consider these two cavities 
to be one and the same as regards these hydroids? 
Compare with Hydra. What means of offence and of 
defence have these hydroicls ? Of distribution ? Which 
do you regard as the higher animal, a campanularian 
hydroid or a hydra ? Why % How much of the colony 
do you regard as an individual animal % Why ? 

Compare with this organism any other hydroids that 
may be available, also the sea-anemone (Metridium). 



Starfish (Asterias Sp.) 

Material. — Living specimens may be found almost 
anywhere along the sea-shore adhering to rocks, timbers 
of wharves, etc. It is best to collect them at low tide, 
as then they are usually near the surface or possibly 
above it; otherwise a dipping-net may be needed to 
reach them. As the starfish lives only in salt water, it 
may be difficult for students living far from the sea- 
shore to procure living animals ; however, if packed in 
an abundance of wet sea-weed and kept cool, living star- 
fishes may be sent to inland schools if not more than ten 
to twelve hours' ride from the coast. On arrival they 
should at once be transferred to sea- water, which may 
be sent in casks from the coast, or to artificial sea-water, 
where they may live for several hours, and thus give 
the student an opportunity to study their habits. The 
water should be kept well aerated. This may easily be 
done by repeatedly pouring from a height dipperfuls 
of the water into the vessel containing the starfishes. 
Specimens for dissection may be prepared in the fol- 
lowing manner : The living animals should be dropped 
into seventy per cent, to ninety per cent, alcohol imme- 
diately after being taken out of the sea-water. The alco- 
hol kills the animal almost immediately, and, as the rays 
retain the various positions which they had just before 
the death of the animal, it is well to select a series of 
specimens which have the rays bent and curved in dif- 

7 



98 THE BIOLOGY OF THE ANIMAL 

ferent directions, in order that the inland student may 
see even in the preserved specimens the wonderful flex- 
ibility of the body and rays of the starfish. Care must 
be taken not to put too many specimens into the vessel 
of alcohol, for the water in the body-cavity and tissues 
of each animal weakens the alcohol a certain amount. 
With ninety per cent, alcohol the bulk of the specimens 
should be not more than one-third of the bulk of the 
alcohol used. After the specimens have lain in strong 
alcohol for an hour or two, insert the needle of a hypo- 
dermic syringe into the roof of each ray, near the tip, and 
fill the cavity of the ray with alcohol. This preserves 
the internal organs in good condition, keeps the ray 
distended in its natural shape, and the hole made by the 
needle does not interfere with dissection ; besides, the 
hole, being very small, becomes plugged up immediately 
after the withdrawal of the needle, and thus the alcohol 
is kept from oozing out, as it would through a larger 
opening. After being in the strong alcohol for two or 
three days, the specimens may be kept indefinitely in 
seventy per cent, to ninety-five per cent, alcohol. For 
the study of the hard parts alone, however, it is well 
to use dried specimens. These are prepared by taking 
some of the alcoholic specimens treated as above, and 
laying them for a day or two in the hot sun or in an oven. 
If dried in the open air, they should not be left out of 
doors overnight nor allowed to become damp. For the 
study of the structure and arrangement of the individ- 
ual portions of the skeleton alcoholic or dried specimens 
may be soaked for a few days in a ten per cent, solution 
of potash. As soon as the soft parts commence to mace- 
rate, the specimens may be carefully brushed with a 
ragged tooth-brush in order to remove the skin and 
flesh. If soaked too long, the skeleton will drop to 



STAKFISH 99 

pieces. When thoroughly cleaned, rinse the skeleton in 
fresh water and put it into strong alcohol for four or 
five hours, then dry in the open air or over a stove. 

For the study of the water -vascular system, injected 
specimens should be prepared. A very convenient 
method is to kill the starfish in fresh water; after the 
animal is dead warm the water up to the melting-point 
of gelatin, cut off the tip of one of the rays, insert the 
tip of a fine-pointed syringe into the end of the radial 
water-tube, and with a slow but firm pressure fill the 
water-vascular system with a carmine or Prussian-blue 
injecting mass. Specimens thus prepared may then 
be hardened in alcohol, where they will keep indefi- 
nitely. 

For the microscopical examination of cross-sections of 
the rays and disk, small specimens one-half inch to an 
inch in width should be provided. They may be found 
on rock-weed, eel-grass, the surface of the mud, etc., in 
quiet pools along the sea-shore during the summer 
months. They should be quickly picked off the surface 
to which they are adhering and instantly dropped into 
strong alcohol (ninety-five per cent, to one hundred per 
cent.) and left for four to six hours. The alcohol causes 
instant death, and the ambulacral feet and tentacles re- 
main expanded. The specimens may then be placed in 
one -half per cent, to one per cent, chromic acid for 
about twenty -four hours, or at least until no more bub- 
bles arise, showing that the acid has dissolved all or 
nearly all of the calcareous part of the body, and left it 
in condition to be cut with a sharp knife. The starfish 
is then placed in seventy -five per cent, alcohol for a 
day, then into ninety per cent, for another day or until 
wanted for examination. Specimens may be embedded 
in paraffin, or in celloidin, and cut on the microtome. 



100 THE BIOLOGY OF THE ANIMAL 

They may be stained in borax carmine either before or 
after cutting, or left unstained as desired. 

The larval forms of the starfish may be obtained 
along the New England coast from June to September, 
by skimming, or they may be raised from the eggs. 
Yery small starfishes, suitable for study with the micro- 
scope, may be found attached to eel-grass during the 
summer. If a number of starfishes be caught during 
the time mentioned and be kept for a few hours in a 
pail of sea- water, some of them will probably be found 
to be discharging eggs or sperm. The former may be 
distinguished by their pinkish color ; the latter is white. 
About a teaspoonful of the eggs may be thoroughly 
mixed with a few drops of sperm in a tumblerful of 
sea-water and set in a cool place. By means of a pi- 
pette the water should be changed three or four times 
a day and aerated frequently. Some of the eggs may 
be taken out from time to time to watch the process of 
segmentation, or this process may be studied in eggs 
fertilized on the slide. Eggs in various stages of seg- 
mentation may be taken from the tumbler at intervals, 
and preserved for further study after treatment as fol- 
lows : Place the eggs for ten or fifteen minutes in Klei- 
nenberg's picro-sulphuric acid (undiluted); transfer to 
thirty-five per cent., then to fifty per cent., alcohol each 
for an hour ; then place them in seventy per cent, alco- 
hol, and change the latter as often as it becomes dis- 
colored. Such specimens may be stained in Delafield's 
hematoxylin. Spermatozoa, and eggs showing the for- 
mation of the polar globules, seldom preserve satisfac- 
torily. Another method of obtaining eggs and sperm 
is to cut open the body, remove the egg and sperm- 
glands, and chop up the glands together in a watch-glass 
of water, or chop them separately and mix them after- 



STARFISH 101 

wards. The shreds of tissue should be removed, as their 
decay will pollute the water. Unfertilized eggs as well 
as those in various stages of development may, however, 
be preserved as alcoholic specimens for inland students 
to study. 

A large scalpel or cartilage knife, a small scalpel, fine 
forceps, bristles, fine scissors, ten per cent, hydrochloric 
acid, test-tube or watch-glass, hand-lens, compound mi- 
croscope, borax carmine, and Delafield's hematoxylin 
will also be needed. 

Method of Examination. — Fresh specimens should be 
placed in a large vegetable dish of sea-water, which 
should be frequently renewed. Alcoholic material may 
be examined in a dish or dissecting-pan containing 
enough fifty per cent, alcohol to cover the specimen. 

MORPHOLOGY 

External anatomy. — With a fresh or alcoholic spec- 
imen study 

a. Shape. — Is the shape that of a perfect star ? Does 
it have a definite number of rays? Are all of 
the rays on a normal specimen of the same 
shape, size, etc. ? What differences in shape 
between the under or oral and upper or aboral 
sides? How do you account for the extreme 
differences in the size of the body and rays of 
certain specimens? For the differences in the 
number of rays? Does the animal have a head ? 
"What significance has the common name? Is 
the animal a fish ? Is the body bilaterally or 
radially symmetrical? 
Draw both oral and aboral surfaces. Make outline 



102 THE BIOLOGY OF THE ANIMAL 

drawings of several specimens to show the normal shape 
and abnormal variations. 

b. Size. — What is the size of an ordinary specimen? 

Can you tell anything about the age by the 
size? 

c. Color. — What is the natural color? Are all the 

living specimens colored alike ? Is the color the 
same all over the body? Are there any color 
markings on the body ? What changes of color 
take place when the specimen is dried ? 

d. Structure. — The central part of the body is called 

1. The disk.— What is its shape? How does its 

oral differ from its aboral side ? 

On one side of the disk find a circular 
plate, 

2. The madreporic body — Position ? Shape ? 

Size ? Color ? Structure ? 

The two rays which touch the madreporic 
body form 

3. The bivium. — What differences between these 

rays? 
The remaining three rays form 

4. The trivium. — Compare with 3. 

The ray opposite the madreporic body is 
called 

5. The anterior ray. — Compare in shape, size, 

and structure with the other rays. 

6. The spines (in studying these a dried speci- 

men should be used for comparison). — On what 
part of the body are they found ? Are there 
any traces of definite arrangement ? How 
many kinds are there ? What is their shape ? 



STAEFISH 103 

Size ? Structure ? Are they fixed or movable ? 
If the latter, what kind of joint have they? 
Do you find any spines which seem to be spe- 
cially adapted to certain purposes? Notice 
the five clusters of spines around the mouth, 
forming the mouth-papillee. 
Draw one of each kind of spine seen lengthwise. 

7. The skin. — Does it cover all parts of the body? 

Examine its texture. What is its color? Do 
you find any variations in thickness ? Is it 
loosely or closely attached to the hard parts of 
the body? With fine forceps remove a small 
piece of skin from the body of a living starfish 
and examine in a drop of sea- water w r ith the 
high power. Note the columnar ciliated 
epithelium. 

Among the bases of the spines find 

8. The aboral tentacles. — How are they ar- 

ranged on the body ? How do they compare 
in shape, size, and structure with the ambula- 
cral feet ? Is their surface ciliated ? 

9. The mouth. — What is its position? Shape? 

Size ? Are there any teeth ? Lips ? 

Around the mouth - opening find a mem- 
brane, 

10. The peristome. — Shape ? Structure ? Color ? 

Is it flexible ? Does it bear any structures ? 
On the oral side of the rays look for 

11. The ambulacral grooves.— What is their po- 

sition on the ray ? Shape ? How are they 
formed ? What is their relation to the mouth ? 
How far do they extend ? Where is the deep- 
est part of the groove? Where the shallow- 
est? 



104 THE BIOLOGY OF THE ANIMAL 

In the grooves are 
12. The ambulacral feet. — How are they arranged 
in the groove? What is their shape? Size? 
Do you find any variations in shape or size? 
Color ? Structure ? Are they found anywhere 
else than in the grooves? Pull off a foot and 
insert a fine bristle into the torn end. Notice 
that the foot is tubular. Examine one of the 
feet under the low power of the microscope, 
and note at the extreme end the thickened 
ring with the creased central membrane form- 
ing a sucking disk ; also the circular ridges in 
the walls of the tube, the groups of circular 
muscles. Can you determine whether any or 
all of the feet are connected ? Sketch a longi- 
tudinal section of an ambulacral foot magni- 
fied. Make an enlarged drawing of the sucking 
disk to show its structure. 

Lying just above a membrane stretched 
across the roof of the groove find 

13. The radial water-tube. — How far does it ex- 

tend? Pass a fine guarded bristle into its 
cavity and trace the course of the tube. Ex- 
amine injected specimens to see how the radial 
water-tubes are connected with one another. 
Along with the water-tube run a " blood-ves- 
sel " and a nerve so intimately connected with 
the tube as to be almost indistinguishable ex- 
cept in trans-sections of the ray prepared for 
microscopic examination. 
Make a diagram of a cross section of a ray. At the 
ends of the rays look for 

14. The eyes. —Position? Shape? Size? Color? 

What is the arrangement of the spines around 
the eye? 



STAKFISH 105 

On the bases of the spines find 
15. The pedicellarise. — What is their exact posi- 
tion with regard to the spines ? What is their 
shape? Size? Are they branched? Put one 
under the low power and examine the struct- 
ure. 
Draw. 

The Skeleton. — In a well-cleaned specimen prepared as 
directed notice 

a. General Structure. — Of what does the skeleton con- 
sist ? How are the parts or ossicles arranged ? 
Do you find any differences in the arrangement 
of the parts on the oral and aboral surfaces ? To 
what are the spines attached ? 
With a sharp knife cut off one of the rays at its 
widest part, and examine its oral surface. 
Forming the roof of the groove find 

h. The ambulacral ossicles. — How are they arranged ? 
What is their shape ? In w r hat direction do they 
run ? Do they bear spines ? Note the openings 
or ambulacral pores, through which the ambu- 
lacral feet pass. Are these openings perforations 
in the ossicles ? If not, how are they formed ? 
Are any two adjacent ambulacral ossicles exactly 
alike in structure? 

Lying immediately outside the above is a sin- 
gle row of 

c. The inter - ambulacral ossicles. — What is their 

shape? Do they bear spines? If so, are these 

spines similar to those on the aboral surface of 

the ray ? 

Next outside the inter-ambulacral ossicles come 



106 THE BIOLOGY OF THE ANIMAL 

d. The " cross - shaped " ossicles. — With what do 

they connect ? What sort of spines do they bear ? 

Do these ossicles consist of a single piece ? Do 

you find any openings through them? 

Cut along each side of the ray and remove the aboral 

portion, and notice in the middle of the floor of each ray 

e. The vertebral ridge— How is it formed? Why 

called " vertebral " ? 
Kemove the top of the disk and note 

/. The mouth-opening.— What is its shape? How 
formed ? How does it compare in size and shape 
with the mouth itself ? 

g. The inter-radial partitions. — How many are there? 
What position have these with reference to the 
mouth - opening ? Of what are they formed? 
Look on each side of each partition for a small 
opening, the inner end of the reproductive ori- 
fice. Push a fine-pointed bristle into the orifice, 
and try to find the outlet of the tube. 

h. The chemical composition of the ossicles. — Drop 
a few of the ossicles into ten per cent, hydro- 
chloric acid in a test-tube or watch-glass. The 
formation of bubbles in the fluid shows that the 
ossicles contain carbonate of lime. Compare with 
the spicules of Spongilla and Grantia. 

Internal Anatomy. — Either fresh or alcoholic speci- 
mens may be used. The organs of the latter, though 
somewhat changed in color, possess the advantage of 
being toughened, and hence are less easily torn. With 
a pair of strong scissors make a transverse cut through 
the roof of the rays of the trivium, near the tip of each. 



STARFISH 107 

Extend the cut along the sides of each ray to the disk, 
in such a manner as to free the roof of the rays and disk 
from the lower part. Be careful not to injure the in- 
ternal organs with the tips of the scissors. Bend back 
the cut portions and notice : 

a. The body-cavity, ccelom, or peri- visceral cavity. 

— What is its shape ? How is it formed % What 
does it contain ? Is it single or divided into com- 
partments ? Note the smooth, glistening mem- 
brane lining the cavity. Examine microscopically 
a drop of fluid from the body-cavity of a living 
starfish. 

A. — The Digestive System. 

a. The hepatic cceca or " liver" (physiologically, a 
pancreas). — How many in each ray % Do they 
entirely fill the ray ? How are they arranged ? 
To what are they attached ? How held in place ? 
What is their color ? Structure \ With what do 
they communicate ? By what means ? 

Attaching the hepatic cceca to the roof of the 
ray is 

h. The mesentery. — What is its position ? How many 
in each ray ? Texture ? Color ? Notice that the 
mesentery is continuous with the membrane 
which lines the body-cavity. Try to prove that 
the membrane consists of a double fold. 

c. The stomach. — What part of the body-cavity does 
it occupy? Note that it is divided into a pouched 
or cardiac portion and a pentagonal or pyloric 
portion. Study the arrangement, shape, size, and 
structure of the pouches. Examine the mem- 



108 THE BIOLOGY OF THE ANIMAL 

brane of which they are composed. Are the 
poaches distensible ? To what are they attached ? 
How does the cardiac compare in size with the 
pyloric portion? Do you find any ingested food 
in the cardiac portion? If so, of what does it 
consist ? Do you find any structures which could 
serve to grind hard food ? Do you find any speci- 
mens in which a part of the cardiac portion pro- 
trudes through the mouth? Look for the re- 
tractor muscles of the cardiac pouches. How 
many are there ? What is their shape ? Length ? 
To what are they attached ? Look for the pro- 
tractor muscles. Compare them with the re- 
tractors. What is the position of the pyloric 
with reference to the cardiac portion? Do you 
notice any difference in the character of its wall ? 
Notice the very short passage, oesophagus, lead- 
ing from the mouth to the stomach. The shape 
of the various portions of the stomach may be 
well seen by proceeding as follows : Remove the 
roofs from all the rays, but leave the roof of the 
disk untouched. Separate the latter along the 
inter -radial partitions, divide the ducts of the 
hepatic coeca, remove the cceca from the body, 
turn the latter upside down, and pour water into 
the mouth. The water will distend the stomach 
and show its shape. 

Near the centre of the aboral side of the py- 
loric portion of the stomach find 

d. The intestine. — What is its shape ? Length? Look 
for the opening, anus, to the exterior. 

Near the intestine look for a brownish saccu- 
lated organ, 



STARFISH 109 

e. The respiratory tree. — Position % Shape ? At- 
tachments ? 
Draw the digestive system alone. 

B. — The jReproductive System. 

At base of ray find the sexual glands, the ovaries 
pinkish, and the testes yellowish-white. 

a. The reproductive organs. — How many in each ray ? 
Do you find both ovaries and testes in the same 
animal ? Compare them as regards arrangement, 
shape, size, color, structure, etc., with the hepatic 
coeca. Where do they open? If possible, com- 
pare specimens collected in summer with others 
taken in the spring or autumn, and note the ex- 
treme differences in the size and color of these 
organs. 
Draw the reproductive system in an outlined body. 

C. — The Water-vascular System. 

If obtainable, examine specimens in which the water- 
vascular system has been injected. Injected specimens 
may be prepared as directed. The madreporic body, am- 
bulacral feet, and the radial water-tubes, all of which 
form part of the system, have previously been examined. 

On each side of the vertebral ridge find 

a. The ampullae or water-sacs. — What is their exact 
position in the ray ? Shape ? Size ? Structure ? 
Tear one open and note that it is hollow. Is its 
wall distensible? Lay a slender pencil in the 
ambulacral groove, so as to compress the ambu- 
lacral feet, and notice the effect upon the am- 
pullae. Is there communication between the am- 
pullae and the feet ? How does the number of 



110 THE BIOLOGY OF THE ANIMAL 

ampullar compare with the number of feet in the 
same way. 

Cut all of the retractor and protractor muscles, 
cut the stomach across just above the peristome, 
and remove all of the digestive organs. 

Running down under the madreporic plate find 

5. The stone-canal. — What is its position? Shape'* 
Size ? Pinch it lightly between the fine forceps. 
What is the nature of its wall ? What does the 
canal connect? Does its end cover the entire 
lower surface of the madreporic plate ? 

Eemove the peristome, and find lying within 
the mouth pentagon 

c. The circum-oral water-tube. — Does it lie without 

or within the body -cavity ? What is its shape ? 
Situated upon the circum-oral tube look for 

d. The Polian vesicles. — How many are there? What 

is their relation to the bases of the rays ? 

Extending horizontally into the cavity sur- 
rounding the oesophagus find 

e. The racemose vesicles. — How do they compare in 

position and size with the Polian vesicles ? How 
many are there ? How do you account for this 
number ? 
Make a drawing of the water-vascular system in an 
outlined body. 

D. — The Circulatory System. 

Enclosing the stone canal find a tube, 

a. The pericardium. — To what is it attached? What 
is the nature of its wall ? 

Lying within the pericardium look for 



STARFISH 111 

b. The heart. — How does it compare in size with the 
stone canal? Remove the heart from the body 
and examine under the low power of the micro- 
scope. What is the structure of the heart ? 
By injecting into the pericardium with a fine syringe 
a colored fluid, such as water containing carmine or in- 
digo, the course of some of the peri-haemal tubes 
which surround the true blood-vessels may be made 
plain. It will then be seen that there is (1) a eircum- 
oral peri-haemal tube surrounding the mouth just be- 
low the circum-oral water-tube ; (2) a radial peri-hae- 
mal tube running from (1) to the tip of each ray, like- 
wise just below the radial water-tube ; (3) a circum- 
anal peri-haemal tube, which is on the inside of the 
aboral surface of the disk, and is larger than the peri- 
haemal tube around the mouth. Its branches run to the 
aboral end of the pericardium, the stomach, the hepatic 
cceca, and the reproductive organs. 
Make a diagram of the circulatory system. 

E. — The Respiratory System. 
Remove a piece (about one-half inch square) of the aboral 
wall of a ray, and carefully examine under water 
the depressions on its inner surface. Look for 
small openings in these depressions, and try to see 
if these openings bear any relation to the aboral 
tentacles on the outside of the ray. If necessarj T , 
use a fine bristle. Try to pass the bristle through 
one of the openings to see if the latter communi- 
cate with the tentacles. Carefully peel off the lin- 
ing membrane. What effect has this operation on 
the tentacles ? Notice that a tough membrane con- 
taining the ossicles remains. In the same manner 
remove the covering membrane on the outside. 



112 THE BIOLOGY OF THE ANIMAL 

What becomes of the tentacles ? What lies below 
this outer membrane ? Putting together the facts 
just learned, what can you say is the structure of 
an aboral tentacle ? What is the structure of the 
membrane containing the ossicles ? Does this mem- 
brane extend down between the ossicles, or does 
it merely cover their upper and under surfaces ? 

F. — The Nervous System. 
With a lens carefully examine the lower surface of the 
circum-oral water-tube for a thickened ridge, the 
eircum - oral nerve -ring, running around its 
outer surface. Eunning from this ring just be- 
low, i. e., outside, the radial water-tube in each 
ray is a radial nerve which extends to the tips 
of the ray and ends at the eye. The relation of 
this nerve to the neighboring parts is much bet- 
ter seen in cross-sections of the ray prepared for 
microscopic examination. 

PHYSIOLOGY 

Nearly all of the following work must necessarily be 
done on the living animals. They should be studied 
among their natural surroundings whenever possible, 
otherwise in an aquarium well supplied with an abun- 
dance of running sea- water. 

Experiments requiring the removal of portions of the 
body of the living animal probably cause little if any 
pain, since the starfish frequently parts with one or 
more of its rays voluntarily. 

A. Movements. — What sort of motion has the starfish? 
How rapidly can it move ? What are its organs 



STARFISH 113 

of motion ? Can it swim ? Does it always move 
with the same ray ahead \ Study the movements 
of a single ambulacral foot. Are all of the feet 
used for progression ? Are the rays flexible ? If 
so, in what directions do they bend? Turn a 
specimen over on its aboral surface. Through 
what motions does it go in righting itself? Does 
the starfish lose the power of locomotion when 
removed from the water ? Can it bend its rays 
under such circumstances ? 

B. Nutrition. — Look along the wharves at low tide for 
clusters of mussels on which starfishes may be 
found. Examine such a starfish to see if the 
cardiac portion of the stomach is not protrud- 
ing and partially enwrapping a mussel. See if 
you can find that the stomach or disk moves at 
all. Quickly pick the starfish off the mussel 
and watch the withdrawal of the stomach into 
the body. How soon does it take place? In 
studying the internal anatomy, did you find any 
structures which could bring about this move- 
ment of the cardiac pouches? Do you find any 
specimens which though not feeding have the 
stomach protruding? Examine the stomachs of 
a number of fresh or alcoholic specimens for the 
shells of small molluscs. Do these shells bear 
any evidence of having been broken to pieces 
in the body of the starfish? Judging from the 
structure of the mouth-parts and of the stomach, 
what kind of food is the animal fitted to eat? 
Starfishes kept in an aquarium may sometimes 
be found feeding on other small animals kept 
in the same tank. 
8 



114 THE BIOLOGY OF THE ANIMAL 

C. Nervous Properties. 

a. Touch. — Does the starfish seem to feel objects 
with which it comes in contact as it moves 
about? Touch one of the feet with a pencil 
point or a bristle. Is the foot sensitive ? In like 
manner touch one of the aboral tentacles. What 
happens? With a hand-lens find a large pedi- 
cellaria and touch the end of it with a fine 
bristle. What does the pedicellaria do ? Do you 
find any organs which appear to be specialized 
as organs of touch? If so, where are they and 
from what have they been modified? 

b. Sight. — Put a number of vigorous starfishes into 
a tank of sea-water and allow them to disperse 
at will. Note their positions, then cover the 
tank with thick cloth to exclude the light, leav- 
ing only a small aperture, two or three inches 
in diameter, at one end for a small amount of 
light to enter. After a time, fifteen minutes to 
several hours, look into the tank to see if the 
animals have changed their positions ? Are they 
attracted by the light ? How do you tell ? From 
several starfishes carefully remove the eyes, no- 
ticing particularly the behavior of the surround- 
ing spines, and put the animals into a tank pre- 
pared as above. Do they now pay any attention 
to the light ? Have you any reasons for thinking 
that these animals can perceive small objects ? 

c. Hearing, taste, and smell. — Do any of your ob- 
servations lead you to suppose that the starfish 
possesses these powers ? 

d. Co-ordination. — Examine a moving starfish and 



STARFISH 115 

note that the various rays and the multitude of 
ambulacral feet all move in such a way as to 
attain a common object. Study also the co- 
ordinated movements by which a starfish rights 
itself after having been overturned. Where 
does the righting movement begin? Does it 
ever begin on opposite sides of the body at the 
same time? Overturn the same animal repeat- 
edly and see if the righting movements always 
begin on the same side of the body. With a 
pair of scissors remove one or more of the rays 
from the body of a vigorous starfish and put the 
parts back into the water. Does this treatment 
kill the starfish ? Have the detached rays or the 
body lost their powers of motion, sensation, co- 
ordination, etc. ? What is the direction of the 
motion of a detached ray? Of the body with 
the remaining rays ? How do you explain this ? 
Find a specimen which is progressing in a defi- 
nite direction, and prick the skin on that side 
of the body towards the point to which the an- 
imal is going. Does the animal change its 
course ? 

D. Reproduction. 

I. Regeneration of lost portions of the body. — With a 
pair of scissors or a sharp knife remove one of the 
rays close to the disk. Place the parts back into 
the water and study their behavior. What takes 
place at that part of the disk where the ray was 
removed ? Watch the mutilated parts from day 
to day to see what changes are going on at the 
point of injury. How long before the opening 
into the body-cavity caused by the removal of the 



116 THE BIOLOGY OF THE ANIMAL 

ray is closed? How long before you can find 
evidences that a new ray is being formed to re- 
place the one removed ? Does this new ray ever 
reach the size of the others ? If so, in how long 
a time? How many rays may be removed and 
still be replaced by new ones ? Do the removed 
rays ever form a new disk, etc. ? Try handling 
out of water large starfishes and see if they will 
voluntarily drop their rays. If so, at what point 
does the ray become detached ? Is this property 
of any use to the animal ? 
Many of the above questions may be decided by a 
study of a collection of specimens of imperfect and mu- 
tilated starfishes. 

7Z Sexual reproduction, 
a. The structure of the sexual cells. 

1. The spermatozoon. — With a pipette collect 
some of the sperm which a mature male may 
be found shedding into the water, or remove 
the testes and with sharp scissors cut them 
to pieces in a watch-glass of sea-water. Put a 
drop of the sperm under the high power of the 
microscope, propping up the cover-glass with 
bits of wax or paper, and note the spermatozoa. 
Are they abundant or few? What sort of 
motions do they exhibit? Study their struct- 
ure and endeavor to make out the head — its 
shape and relative size ; and the tail — its shape 
and movements. Can you discover a cell-wall ? 
Endeavor to stain the spermatozoa with he- 
matoxylin. What part becomes most deeply 
stained ? Is this part a nucleus ? 
Draw a spermatozoon. 



STARFISH 117 

2. The ovum. — Collect some ova in the manner de- 
scribed for spermatozoa. Put them under the 
low power and note their shape, size, color, etc. 
Is an ovum large enough to be seen without 
the microscope ? Put on the high power and 
study their structure. Can you, with or with- 
out reagents, make out a cell- wall, protoplasm, 
and nucleus % Does the egg sink to the bottom 
or does it float? Compare ovum and sperma- 
tozoon as regards shape, size, color, structure, 
motions etc. What reasons can you suggest 
for the differences ? 
Draw an unfertilized, i. e., ovarian, ovum. 

b. Preparation of the ovum for fertilization. 

1. The formation of the polar globules or i ' direc- 
tion-cells." — Examine a number of unfertil- 
ized living ova to see if some cannot be found 
which are pushing out a small protuberance at 
one margin of the yolk (protoplasm), just under 
the membrane or cell-wall. This prominence in- 
creases in size, and finally becomes divided off 
from the surface of the yolk as the " first polar 
globule." Soon afterwards a second is formed 
in the same manner, and the two come to lie 
side by side under the egg-membrane. Each 
globule contains a portion of the nucleus of the 
ovum. Stain some of the ova Avith carmine or 
haematoxylin to prove this last statement. The 
process of the formation of the polar globules 
is known as the " maturation of the ovum " ;* 

* A process somewhat similar to this has been seen to take place 
in the spermatozoa of certain animals. 



118 THE BIOLOGY OF THE ANIMAL 

in this manner the ovum becomes fitted for 
the reception of the sperm-cell (fertilization). 
How do the polar globules compare in size 
with the ovum ? Do you ever find that more 
or fewer than two are formed? How long 
does it take the first one to form? The 
second? Does the second form in the same 
place as the first ? Always ? Can you suggest 
any reasons why the polar globules are formed ? 
Draw the different stages of formation of the polar 
bodies. 

c. Fertilization. 

1. The union of the sexual cells. — Mix together on 
the slide a drop of water containing a few eggs 
and one containing spermatozoa, put on the 
cover-glass supported by bits of wax, and 
examine under the high power. How do the 
spermatozoa behave ? How the ova ? Note 
that the most of the sperm-cells collect around 
the eggs. Can you see the entrance of the 
sperm-cell into the egg ? Does it take place at 
any particular point ? How many sperm-cells 
enter the same egg ? Notice that a short time 
after the sperm and ova are mixed a clear area 
appears between the wall and the contents of 
certain ova. These ova have been fertilized, 
although the entrance of the spermatozoon 
may have escaped observation. 

d. The consequences of fertilization. 

1. The first division or segmentation of the ovum. — 
A few minutes after the sperm and eggs have 
been mixed some of the latter will show a 
notch beginning to form at one margin of the 



STARFISH 



119 



yolk. This is the first external indication of 
the division of the egg. What relation has the 
position of this notch to that of the " direction- 
cells " ? Can you suggest a reason why these 
are called " direction-cells " ? Watch the notch 
as it deepens into a furrow. In what direction 
and how far does the furrow extend? How 
long before it divides the yolk into two distinct 
parts, blastomeres ? What is the shape of 
each of these ? Can you distinguish a nucleus 
in each part? Try reagents if necessar} 7 . 
Does this division have any effect upon the 
membrane ? Do all of the eggs with which 
you have mixed sperm begin to divide at the 
same time, and does the process go on with the 
same rapidity in all ? 
Draw. 

If reagents were applied while watching the first seg- 
mentation, fresh specimens must be taken for the fol- 
lowing stage : 

2. The second division. — How long before the 

second division begins ? What is the first in- 
dication that a second furrow is beginning to 
form? What is its direction with respect to 
the first ? How long before the egg is com- 
pletely divided by this furrow? How many 
cells are there now inside the egg membrane ? 
Draw different stages of the second segmentation. 

3. The third division. — Compare this with the first 

two as regards the various features mentioned. 
Draw. 

4. The blastula. — After a few hours, during which 

successive divisions take place, the egg will be 
seen to consist of a solid spherical mass of cells 



120 THE BIOLOGY OF THE ANIMAL 

which after a time will push out from the cen- 
tre of the sphere, thus forming a hollow sphere, 
the cavity now enclosed by the layer of cells 
being known as the segmentation-cavity. 
"When the egg has reached this stage of develop- 
ment it may require careful focussing to show 
that the sphere is really hollow. Does the mem- 
brane still surround the egg 9 i Has the egg 
increased in size % Can you detect any move- 
ment of the egg as a whole or of the sphere 
inside the egg membrane ? 
Draw a blastula as seen from the surface and in op- 
tical section, i. e., as though one-half the sphere were 
removed, leaving the cavity visible. 

5. The gastrula. — At the end of about twenty- 
four hours after fertilization, or perhaps soon- 
er, it will be noticed that at a certain point 
the surface of the blastula becomes indented as 
though being pushed in (invagination). The 
depression increases, and the invaginated mass 
of cells encroaches upon the segmentation cav- 
ity. The depression is the primitive mouth or 
digestive cavity of the embryo or gastrula, 
which now consists of two layers of cells, the 
original outer layer, or ectoderm, and the lay- 
er of invaginated cells, or entoderm. Between 
these layers lies the segmentation cavity, while 
the entoderm lines the digestive cavity. In 
this stage the cells of the ectoderm will be 
seen to be covered with cilia, by means of 
which the embryo rotates within the egg- 
membrane. The membrane soon breaks, and 
the embryo swims about freely in the water. 
Before this happens it may be noticed that the 



STARFISH 121 

entoderm cells are giving off amoeboid cells, 
which move about in the segmentation cavity, 
and finally form a third layer, or mesoderm, 
between the other two. 
Draw a gastrula. 

6. The later larval stages. — If material be obtain- 
able, the student can trace the change of the 
gastrula into the Bipinnaria stage, and from 
this the development of the young starfish, 
noting especially the extreme changes of form 
and structure, and drawing each stage. 

Use the sand-star (Ophiqpholis), sea-urchin (Echinus 
or Arbacia), sand -cake (Echinarachnius), and sea -cu- 
cumber (Pentacta). The examination of the skeletons 
of the first three is especially instructive, and a very 
valuable and interesting study may be made of the 
manner in which the same fundamental plan of struct- 
ure is modified in various ways in these different organ- 
isms. 



Earthworm (Lumlricus Sp.) 

Material. — Both living and alcoholic material should 
be at hand. The first may be obtained almost any- 
where in firm, damp soil during the warm months of 
the year, especially from June to September, during 
which time the worms are breeding, and on warm 
nights are very likely to be found lying on the sur- 
face of the soil, with the most of the body outside the 
burrow. At this time a large number of fine specimens 
may frequently be caught by quietly examining the 
ground in a garden or lawn. It is necessary to step 
carefully, as the slightest jar disturbs the animals, and 
they immediately withdraw into their burrows. Larger 
and more perfect specimens may usually be caught in 
this way than by digging. A number, at least five or 
six for each student, should be obtained, and those 
which are to be preserved in alcohol should first be 
put into a basin of water and the dirt rinsed off their 
bodies, then they should be put for twelve hours into 
three to five times their bulk of fifty per cent, alcohol 
in a flat dish, in which they may be laid out straight. 
Transfer to seventy-five per cent, alcohol for a day, and 
then to strong alcohol for preservation. In winter, liv- 
ing worms may be found in the soil or under flower- 
pots in greenhouses. Specimens may be kept alive for 
study in the winter by putting them into large, well- 
drained flower-pots filled with fairly stiff soil contain- 
ing a few dead leaves and covered with a sod. The 



EARTHWORM 123 

flower-pots should stand in a cool, light place, as in a 
cellar window, and should be watered sufficiently to 
keep the soil damp, but not saturated. From time to 
time small pieces of cabbage and of lettuce-leaves may 
be placed upon the sod for the worms to feed upon. 
Other material needed includes a clissecting-pan, fifty 
per cent, alcohol, hand-lens, fine forceps, fine scissors, 
magenta, acetic acid carmine, muriatic (hydrochloric) 
acid, a rough, unplaned board, a sheet of sand-paper, 
pipette, and compound microscope. 

Method of Examination. — Living worms may be 
placed on a dissecting-tray or in a dissecting-pan for 
examination, and their bodies must be moistened with 
water from time to time. To study its method of bur- 
rowing, place the worm on the surface of moistened and 
fairly compact soil in a flower-pot. The course of the 
burrow may afterwards be traced by carefully picking 
away the soil, beginning at the opening. 

Preserved specimens are best for the study of the 
morphology of the animal, and should be examined in 
a dissecting-pan containing enough fifty per cent, alco- 
hol to cover the body of the worm. If the preserved 
specimens are too rigid when first taken out of the 
alcohol, they may be soaked in water for an hour or 
so until flexible. 

MORPHOLOGY 

External Characters, 
a. General shape. — What is it ? Does it vary in dif- 
ferent parts of the body ? Can you distinguish 
an anterior and a posterior end? How? Is there 
a "head"? Can you distinguish a dorsal and 
a ventral surface? How? A right and a left 



124 THE BIOLOGY OF THE ANIMAL 

side? How? "What is the length of the speci- 
men examined? Where is the circumference 
of the body greatest? Where least? What is 
the shape of a cross-section of the body made 
through the largest part ? 
Make an outline drawing, twice natural size, of the 
worm seen from above, and of the cross-section. 

b. Color. — What is the general color of the body ? What 
* differences in different regions ? Can you give any 

reasons for these differences ? 

c. General structure. — Into how many distinct regions 

may the body be divided ? Do these regions 
have any characters in common ? How many 
segments or somites in each region ? Is the 
number constant ? Compare several specimens to 
determine. How do you distinguish one somite 
from another ? Does the individual segment bear 
any markings ? Where is the most muscular part 
of the body, as determined by the firmness of the 
body- wall ? How many segments in this portion ? 
How do they compare in size with those of other 
regions ? In color ? What is the number, count- 
ing from the front, of the largest segment of the 
body ? Of the smallest ? Do you find any seg- 
ment which is not a complete ring? Has the 
body any protective covering or exoskeleton ? 
Are there any jointed appendages, e.g., legs, on 
the body? Are there any respiratory organs, 
e. g., gills, visible on the surface? Any organs 
of hearing or of sight ? 
On your outline drawing indicate the various regions, 

placing the exact number of segments in the first two 

regions. 



EAKTHWOEM 125 

d. The girdle, clitellum, or cingulum. — Does it show 

equally well on all of several specimens % How 
is it distinguished by shape, size, color, etc., from 
the other regions ? Does it completely encircle 
the body? How many segments in it? Is the 
number constant ? Counting from the anterior 
end, with which segment does the girdle begin ? 
With which does it end ? 

e. The cuticle. — Soak an alcoholic specimen in water 

for a few minutes, then with the point of a nee- 
dle or with fine-pointed forceps strip some of the 
cuticle off the body. What is its color ? Its text- 
ure ? Is it easily torn ? Is it flexible or rigid ? 
Opaque or transparent ? Does it cover the en- 
tire body? Does it end at the mouth and anus? 
In its structure is the cuticle well-adapted to the 
earthworm's mode of life ? Examine some from 
the ventral surface in a drop of water and note 
the cuticular sacs in which the setae are partly 
embedded. How are these sacs arranged ? What 
is their shape ? Examine the cuticle under a high 
power and note the striae which mark its surface. 
In which direction do they run ? To what is the 
color of the cuticle as seen by the unaided eye 
due? 
Make a drawing of a portion of the cuticle as seen 
under a high power. 

/. The bristles or setae. — Draw the worm backward 
through the fingers and note the presence of the 
rough points. Examine them with a hand-lens. 
On what part of the body are they found ? How 
are they arranged ? How many in each segment ? 



126 THE BIOLOGY OF THE ANIMAL 

Do you find them in all segments ? In which di- 
rection do they point ? Do all point in this di- 
rection ? How many setse in the girdle ? 

Remove a seta from an anterior segment, 
mount it in a drop of water on a slide, and ex- 
amine under a low power. What is the shape 
of a single seta? How do its ends differ? Is 
the seta attached to the cuticle? Examine un- 
der a high power and study the structure. 
Draw a seta magnified. 

<j. The apertures. 

1. The mouth.— What is its position? What is 

the direction of the opening ? Shape ? Ex- 
amine the prostomium or proboscis. What 
is its position ? Shape ? How formed ? Exam- 
ine the peristomium with a lens. What is its 
structure ? 

2. The anus. — Position? Shape? Compare with 

the mouth. 

3. The dorsal pores. — Strip the cuticle off the 

dorsal surface and look for these pores in the 
median line in the grooves between the seg- 
ments. They may frequently be detected by 
gently squeezing the worm between the fin- 
gers, which causes some of the fluid of the 
body -cavity to ooze out of these openings. 
How many pores does each segment have ? 
Are all of the segments provided with them ? 
Where is the first pore ? The last ? 
Indicate the pores on your outline drawing. 

4. The sexual apertures. 

{a) The opening of the vas deferens or duct of the 
testis.— With a lens look for a pair of openings, 



EARTHWORM 



127 



one on each side, external to the ventral setae 
in the fifteenth segment. What is the shape 
of the opening ? Direction ? 

(b) The opening of the oviduct or duct of the ovary, 
situated similarly to (a), but in the fourteenth 
segment. Compare with (a) in all respects. 

(c) The openings of the spermathecce or seminal re- 
ceptacles, two pairs of openings situated in a 
line with the outer row of bristles and in the 
grooves between segments nine and ten, and 
ten and eleven, one pair in each groove. Com- 
pare with (a) and (5). 

Make an outline drawing of the body as before, but 
of the ventral side, indicate the number of segments 
back to the girdle, and the openings of the sexual or- 
gans. 

(d) The capsulogenous glands. — The swollen ven- 
tral surface of segments nine to eleven or 
sometimes eight to twelve is due to the pres- 
ence of these glands. 

Internal Anatomy. — Put the largest available pre- 
served specimen into a dissecting-pan with enough fifty 
per cent, alcohol to cover the worm. Pin the body 
out straight, dorsal side uppermost, thrusting the pins 
through the first and one of the last segments. With 
a pair of sharp, fine-pointed scissors cut through the 
body-wall along the median dorsal line from about 
the seventieth to the first segment. Carefully cut the 
membranous partitions or septa at the points where 
tbey join the body-wall, and pin back the flaps of the 
latter. Notice that the body- wall forms a tube in 
whose cavity, the body-cavity or peri- visceral cav- 
ity, lies another tube, the alimentary canal ; also that 



128 THE BIOLOGY OF THE ANIMAL 

the septa divide the body-cavity into smaller cavities. It 
is well to have also a second, well -hardened specimen, 
whose body has been divided accurately along the 
middle line, thus making a longitudinal section through 
the entire alimentary canal to show the internal ar- 
rangement of its parts. 

a. The body- wall. — Of what is it composed ? How 

many layers are distinguishable? What is its 
color ? Are all of the layers of the same color ? 
What relation has the color of the body- wall to 
that of the surface of the body ? What varia- 
tions in the thickness of the wall ? Does it con- 
tain any bony or shell-like bodies ? 

With a sharp knife cut a well-hardened speci- 
men in two at the most muscular portion of 
the body. Then cut a thin transverse section 
and lay it on a slide in a drop of fifty per cent, 
alcohol or glycerine, and examine with a low 
power. Note the layers of the body-wall, es- 
pecially the circular and longitudinal muscles, 
the latter projecting like a fringe into the body- 
cavity. 

b. The body -cavity. — How is it formed ? What 

organs does it contain? Is it a continuous 
cavity? Has it any communication with the 
exterior ? Kill a worm by drowning or by ex- 
posure to chloroform vapor under a tumbler, 
cut through the body-wall of some of the poste- 
rior segments, and with a pipette or a glass rod 
collect some of the fluid (peri -visceral fluid) 
found in the body-cavity. What is the color 
of the fluid ? Is it very abundant ? Put a drop 



EARTHWORM 129 

of it on a slide, put on the cover-glass, and ex- 
amine with a low, then with a high power. Note 
that the fluid consists of a watery part, the 
serum, in which float numerous amoeboid cells, 
the corpuscles, as well as various Protozoa, small, 
thread-like worms, fragments of tissue, etc. The 
corpuscles may be stained with magenta or with 
acetic acid carmine if desired. Does the peri- 
visceral fluid coagulate when exposed to the air? 
Draw several of the cells and other bodies found. 

g. The mesenteric septa. — Position? Shape? What 
is their relation to the constrictions between the 
somites in different regions ? What is their re- 
lation to the alimentary canal? Why are they 
called " mesenteric " ? What is their structure ? 

A. The Digestive System. 

What is its position in the body? General shape? 
How do its parts lie with reference to one another? 
Make out the following parts in order. 

The first two or three segments are occupied by 

a. The buccal cavity. — How formed ? Shape ? 

How are its walls connected to the body- wall? 
Does it contain any teeth ? How is it separated 
from the pharynx ? 

b. The pharynx. — Shape ? Size ? Through what 

segments does it extend? What is the nature 
of its wall ? How is it held in place ? 

c. The oesophagus or gullet. — What is its shape? 

Structure ? In what segments does it lie ? Is its 
calibre the same throughout its entire length ? 
In segments eleven and twelve look for 
9 



130 THE BIOLOGY OF THE ANIMAL 

d. The oesophageal or calciferous glands. — 

How many ? How arranged ? To what are they 
connected? What is their shape ? Size? Color? 
Structure ? Examine under a low power a drop 
of fluid from one of these glands. What does it 
contain? Put one of the glands into a watch- 
glass or test-tube containing one part of muriatic 
acid to four parts of water. What result ? Ex- 
plain. 

e. The crop. — Position? Shape? What is the nat- 

ure of its wall? What reasons can you give for 
this ? What is the color of the crop ? What is 
the cause of this color? What does the crop 
contain (use microscope) ? 
Make drawings of some of the contents found. 

/. The gizzard. — In what segments does it lie ? 
Compare in all respects with e. 

g. The intestine. — What is its course in the body? 
In which segment does it begin ? Structure and 
color ? Do the septa divide it ? Note the " liver " 
(functionally, a pancreas) on top of the intestine. 
What is its shape ? Color ? Structure ? How far 
does it extend ? Open the intestine lengthwise 
a little to one side of the median line, wash away 
the contents carefully with a pipette, and note 
the folded membrane or " typhlosole " hang- 
ing down from the roof. Does the " typhlosole " 
extend throughout the entire intestine? What 
is its shape ? Structure ? Compare microscopi- 
cally the contents of the posterior end of the 
intestine with the contents of the crop, noticing 
especially the amount of vegetable material, such 



EAKTHWOKM 131 

as fibres, groups of cells, starch-grains, etc., pres- 
ent in each. 
Make two sketches of the entire digestive system 
lying in an outlined body, the first showing the diges- 
tive organs as seen from above, the second as seen in 
longitudinal section. 

B. The Circulatory System. 

The student will need to prepare another specimen 
for the examination of these organs, as some of the 
most important are destroyed in the examination of 
the alimentary canal. For this purpose kill a liv- 
ing worm by immersion in alcohol and examine at 
once. Only the more prominent vessels are given be- 
low. 

a. The dorsal or supra-intestinal blood-vessel. 
— Where does it begin ? How far back can it 
be traced ? What is its relation to the septa? 

h. The circum-cesophageal vessels or "hearts." 

—Position? Number? Shape? Color? 

Lying below the alimentary canal, seen by 
pushing the latter to one side, find 

c. The supra-neural or sub-intestinal vessel. — 

Position ? Kelation to the " hearts " ? 

d. The lateral oesophageal vessel. — Compare 

in size with the dorsal blood-vessel. Note 
the branches given off to the pharynx and the 
oesophageal glands. 
Make a diagram of the portion of the circulatory 

system studied, showing its relation to the digestive 

system. 

e. The blood. — Open the body-cavity of a recently 

drowned worm and with two pairs of fine-pointed 



132 THE BIOLOGY OF THE ANIMAL 

forceps pull out one of the " hearts " in such a 
way as to prevent the blood escaping from the 
part included between the two forceps. Place 
this piece of the blood-vessel on a slide, put on a 
cover-glass, and examine immediately under a 
high power. What is the color of the blood? 
Note the serum and the corpuscles. Are the 
latter colored ? To what is the color of the blood 
due ? Compare with the frog's blood in this re- 
spect. What differences between the corpuscles 
found in the blood and those found in the peri- 
visceral fluid ? Put a drop on the slide, but do 
not cover. Does the blood coagulate ? 

Draw some of the blood corpuscles. 

Kemove the alimentary canal from the pharynx to 
the posterior end. 

C. The Nervous System. 

Lying in front of the pharynx find 

a. The supra-cesophageal ganglia or " brain." 

— What is their position? Shape? Are they 
connected ? What is their color ? 

I. The circum - oesophageal commissures or 
" throat-collar. " — Position? How are they 
formed ? What do they connect ? 

c. The ventral nerve - cord. — Position ? How 

formed ? How far does it extend ? What is its 
relation to the intestine ? Eelation to the " throat- 
collar " ? 

On the ventral nerve-cord look for 

d. The ventral ganglia. — What is their position ? 

Shape? How many in each somite? Look for 
small nerves running from each ganglion to the 
body-wall. 



EAETHWOEM 133 

Make a diagram of the part of the nervous system 
studied isolated from the body. 

D. The Excretory System. 

Examine in a drop of water under a low power a sep- 
tum which has been removed from near the oesophagus, 
and find 

a. The segmental organs or nephridia.— Position? 
Number in each segment? Structure? Why called 
" segmental " ? Do they open into the body-cavity ? 
To the exterior ? Is the internal opening in the 
same segment as the body of the nephridial 
tubule? On a septum removed from a living 
earthworm and examined in a drop of water look 
for the nephrostome or nephridial runnel at 
the inner extremity of the tubule. Note the large 
size of the cells forming the funnel ; also the cilia 
with which they are covered. Do the cilia move ? 
If so, of what use is their movement ? 

E. The Reproductive System. 

On septa nine-ten, ten-eleven, and eleven-twelve find 

a. The seminal vesicles. — What is their position? 
Shape ? Are all of the same size ? Do they vary 
much in size in different specimens taken at the 
same time of the year? In specimens taken at 
different times of the year ? What is their color ? 
Carefully remove the oesophagus and notice that 
the lateral vesicles communicate with a median 
vesicle in segment ten and with another in seg- 
ment eleven. 

There will be seen projecting into the front 
of each median seminal vesicle, after removing 
the roof of the same, 



134 THE BIOLOGY OF THE ANIMAL 

b. The testes.— Number ? Shape ? Note the seminal 

funnel opposite each testis and prolonged into a 
tube (vas efferens), these two tubes uniting in a 
single tube (vas deferens) which opens out- 
wardly in segment fifteen. 
Attached to front wall of segment thirteen are 

c. The ovaries. —Position? Number? Size? Color? 

Compare with the seminal vesicles and the testes 
in all respects. Attached to the posterior wall 
of the same segment look for two funnels whose 
tubes, the oviducts, pierce the wall and open ex- 
teriorly in segment fourteen. Close to the point 
where the funnel perforates the wall look for the 
receptacula ovorum. 

Look for small globular bodies in hinder por- 
tion of segments nine and ten, external to the 
seminal vesicles, 

d. The spermathecae. — Compare them with the semi- 

nal vesicles, the testes, and the ovaries. Note 
their openings to the exterior in the grooves be- 
tween segments nine-ten and ten-eleven, close to 
the inner side of the outer double row of setae. 
Make a drawing of the reproductive organs, showing 
them in their proper segments. If facilities are at hand 
for doing such work, sections of embedded specimens 
should be made and the histology of the worm studied. 
This is especially instructive. For this purpose worms 
may be killed in strong alcohol (eighty per cent, to 
ninety per cent.), being left in it for twelve to eighteen 
hours, then cut into pieces about one inch long and 
some of the pieces placed in absolute alcohol for about 
a day. The specimens may then be embedded in cel- 
loidin or paraffin and sectioned. 



EARTHWORM 135 



PHYSIOLOGY 

While studying the live worm be careful to moisten 
its body from time to time with water. 

a. Movements. — Lay a live earthworm on a smooth sur- 
face, as on a planed board or a piece of glass. 
Note the manner in which the worm moves. 
What are its various motions ? Can it move for- 
ward ? Backward ? From side to side ? 

Lay the worm on a rough surface, e. g., an un- 
planed board or a piece of fine sand-paper. Com- 
pare the movements with those made on a smooth 
surface. Is progression any easier than before ? 
Explain. Incline the board at an angle. Can 
the worm climb up the board? If so, at how 
steep an incline ? Hold the worm somewhat 
closely in the hand and study carefully the man- 
ner in which the animai makes its escape. In 
what way do the setae aid it in its efforts ? Put 
a worm in water. Can it swim ? Does it en- 
deavor to get out of the water? Why do we 
find so many worms on the ground after a rain ? 
Place the worm on the surface of the closely, but 
not tightly, packed earth in a flower-pot. Does 
the animal move any more readily than on the 
rough board ? Explain. Note its attempts to 
burrow into the earth. What part of the body 
does it use most? In what manner is this part 
employed ? Is this part especially adapted to 
the purpose in its shape, structure, etc. ? How 
is the rest of the body employed during the act 
of burrowing ? How long does it take to make 
the burrow large enough to contain the entire 



136 THE BIOLOGY OF THE ANIMAL 

body ? What does the worm do with the earth 
while digging? Compare the worm's method of 
burrowing with that of the ant. How do they 
differ? Examine, if possible, different kinds of 
soil, e. g., clay, sand, loam, etc., in a garden, the 
street, or woods, to see which kind the worm 
inhabits, judging from the number of worms or 
of burrows found. When a decision on this point 
is reached, examine the soil to see if it possesses 
any prominent characters by which it is espe- 
cially adapted for the habitation of animals liv- 
ing as the earthworm does. Compare the soil 
with that inhabited by ants. 

b. Feeding. — Put some dead leaves (which must be kept 
moist) on the surface of the earth in the flower- 
pots in which the worms are kept. Notice after 
a day or so, usually in the morning, that some of 
the leaves will be found with their stems or tips 
drawn tightly into the mouths of some of the 
burrows in such a way as fairly to plug the en- 
trance. Pull out one of the stalks, and note that 
its lower end is softened and partly decayed, and 
that it presents a frayed appearance, nearly all of 
the soft tissues having been removed and only 
the fibres left. Watch the flower-pot at night in 
a quiet room, having previously laid some dead 
leaves, scraps of cabbage-leaf, etc., on the surface 
of the soil, and try to see how the worm pulls 
these into its burrow. Gently pinch between the 
fingers the anterior four or five segments of a live 
earthworm and note how the pharynx is everted, 
thus forming a protrusible proboscis by means of 
which the worm can seize hold of things. 



EARTH WOEM 137 

c. Circulation. — Lay a living specimen on a flat surface 
and look for pulsations of the dorsal blood-vessel. 
Where do they begin? In which direction do 
they proceed ? Do you find any portion of the 
blood-vessel which is more contractile than the 
other parts ? 

General Questions. — Does the earthworm have a skel- 
eton? Did you discover any internal organs, as lungs, 
for breathing ? In what way does the worm breathe ? 
Note the resemblance in structure (serial homology) of 
the segments of the body. Can you trace any struct- 
ural resemblance whatever between the earthworm's 
body and your own ? Do you know of any differences 
between a caterpillar (" worm ") and an earthworm? Is 
the former a worm ? Why ? Of what use is the slimy 
fluid which is excreted from the surface of the earth- 
worm's body? If a worm's body be cut in two, does 
each part become an individual animal ? How do you 
know ? From your study of the earthworm, which of 
the special senses would }^ou credit it with having ? Of 
what use, if any, are earthworms to man ? Of what to 
plants? What enemies do you know the earthworm to 
have? How does it protect itself from them? Do you 
know it to be the enemy of any other animal ? Do you 
consider an earthworm to be a " higher " animal than a 
starfish ? Why ? In what ways may the worm be dis- 
tributed geographically ? 

Use the leech (Hirudo) and the sea-worm {Nereis) for 
comparative study. 



Lobster {Eomarus Sp.) or Crayfish (Astacus Sp.) 

Material. — On account of their large size it is better 
to use lobsters than crayfishes. Live lobsters may be 
purchased at the markets of all cities near the seaboard, 
and are often to be obtained inland. They may be sent 
by express if packed in damp sea-weed, and will endure 
a journey of forty-eight hours without difficulty. On 
arrival the packing material should be sprinkled liber- 
ally with sea-water (artificial, if necessary), or the lob- 
sters may be transferred bodily to vessels of such water. 
Should any of the specimens be found to be dead at the 
end of their journey, they should either be examined at 
once or, better, placed in fifty per cent, alcohol for a 
day, being careful to puncture the shell in places to per- 
mit of the entrance of the alcohol to the parts beneath, 
then into seventy -five per cent, and ninety per cent., 
each for the same length of time. They may be pre- 
served indefinitely in the latter grade of alcohol. It is 
possible to use boiled lobsters, but the results obtained 
are seldom satisfactory. Crayfishes may be found un- 
der stones, etc., in sandy and rocky rivers and creeks 
throughout the central portion of the country. Except 
in winter, they may be caught as wanted, or, if to be 
used during the winter, they may be kept in aquaria of 
running water, supplied with plenty of aquatic plants, 
or in a sink into which no refuse is thrown, and be fed 
from time to time with small scraps of fresh meat or 



LOBSTEE OE CEAYFISH 139 

bread. Injected specimens should be used for studying 
the circulatory system. They should be injected before 
being put into alcohol. Drill a hole through the cara- 
pace over the heart, puncture the latter to let out the 
blood, insert the canula of the syringe, and, with a firm, 
steady pressure, inject the starch or gum-arabic injection 
mass. 

Other materials needed are bone forceps, coarse and 
fine forceps, large and small scissors, scalpels, hand-lens, 
compound microscope, bristles, dissecting- needles, acetic 
acid carmine, dilute hydrochloric acid, normal salt solu- 
tion, and small piece of raw meat. 

Method of Examination. — Live specimens should be 
studied in aquaria of sea-water or fresh water as re- 
quired. Individual specimens may be examined in 
glass, earthen, or tin dishes of water. Alcoholic speci- 
mens may be laid on the dissecting-trays or in dishes 
of fifty per cent, alcohol. In the former case it may 
be well to mix about one-fourth part of glycerine with 
the alcohol in which the animal is preserved in order to 
prevent too rapid drying when exposed to the air ; the 
glycerine will keep the tissues and organs moist and 
flexible. 

MOEPHOLOGY 

External Characters : 
A. The entire animal. — What is its shape ? Is it bilat- 
erally symmetrical ? Does it possess well-marked 
anterior and posterior ends \ What is its general 
color ? Compare several specimens to see if you 
can find any decided variations of shape and 
color. After having determined the sex of the 
specimen by studying the appendages (which see), 



140 THE BIOLOGY OF THE ANIMAL 

return again to this point and see if you can dis- 
cover any constant characters of shape, size, etc., 
by which you can tell the sex. What is the aver- 
age size of your specimens? Notice the hard- 
ness of the exoskeleton or "shell.'' Do you find 
all parts of the body covered by it ? Do you find 
the exoskeleton especially modified in places? 
Where ? To what extent ? Notice that the ani- 
mal consists of the body proper and the ap- 
pendages. Note the position of the various 
parts of the body and of the appendages when 
the animal is at rest. 

B. The hody proper. — Note that this consists of an ante- 
rior (cephalothorax) and a posterior (abdomen) 
region. What proportion of the body does each 
occupy? As regards general structure, how do 
you distinguish them? Are both composed of 
joints or segments ? Do both bear append- 
? 



Examine first, 

I. The abdomen. — Of how many joints — i. e., seg- 
ments or metameres — does it consist ? Is this 
number constant? How are the segments con- 
nected? Note the ball-and-socket joint at the 
side. On which segment is the ball ? On which 
the socket ? Are all the segments connected in 
this way ? Are the abdominal segments all alike ? 
Do all bear appendages? How many ^append- 
ages on each segment ? Can you trace any sim- 
ilarity of structure among the appendages ? With 
a sharp scalpel carefully cut away from its fel- 
lows the third abdominal segment, which may be 



LOBSTER OR CRAYFISH 141 

taken as typical, with its appendages, remove the 
contents of the " shell," and note 

a. The segment proper. — What is its shape as seen 

from the end? From the side? How is the 
cuticular covering or exoskeleton modified in dif- 
ferent places ? Make out the following regions 
on the segment : 

1. The tergum, or dorsal portion of segment. — 

What is its shape ? Structure ? Color ? What 
differences between its anterior and posterior 
edges ? 

2. The sternum, or ventral portion of segment be- 

tween the appendages. — Shape ? Size as com- 
pared with the tergum ? Structure ? Color ? 

3. The epimeron, or latero-ventral portion of seg- 

ment external to appendage. — Shape ? Of what 
is it composed ? Color ? 

4. The pleuron, or downgrowth of the side of the 

segment. — Shape? Size? Structure? Color? 
Differences between anterior and posterior mar- 
gins ? What relation does the anterior margin 
bear to the preceding segment ? 

Near the points of union of the tergum with 
the pleura find 

5. The articular facets.— What is their shape? Of 

what are they formed ? How many are there 
on one segment ? What relation do they bear 
to the preceding segment ? 

b. The appendages or " swimmerets." — How many 

on the segment ? What is their position ? Color ? 
How are they attached to the segment ? Make 
out the following parts on each appendage : 



142 THE BIOLOGY OF THE ANIMAL 

1. The protopodite (basal portion). — Of how many 

joints does it consist? How are they connected? 
Of what is the protopodite composed ? Note 

2. The exopodite, attached to the outer margin of 

1, and 

3. The endopodite, attached to the inner margin of 

1. — What is their shape ? Structure ? Color ? 
Do they show any indications of segmentation? 
How are they joined to 1 ? 

Compare the first, second, fourth, and fifth 
abdominal segments with the third in all re- 
spects. Do you find any noticeable variations 
in shape, size, general structure, appendages, 
etc. ? Do you find that all of the appendages 
are constructed upon the same general plan — 
i. e., a basal portion bearing two branches? In 
other words, are the appendages homologous ? 
Draw the third abdominal segment and its append- 
ages as seen from the end. Draw one of the append- 
ages, showing its parts. 

Examine next, 

II. The cephalo thorax. — What is its shape as seen 
from above ? From the side ? Note the covering 
or carapace. Does it show any traces of segmen- 
tation ? Does it entirely cover the cephalothorax ? 
At what points is it attached to the body ? What 
is the structure of its posterior and lateral mar- 
gins? Examine the cervical groove running 
across the carapace. What course does it follow ? 
Note that it divides the carapace into an ante- 
rior or cephalic and a posterior or thoracic re- 
gion. Note also the two branchio - cardiac 
grooves running backward from the cervical 



LOBSTER OR CRAYFISH 143 

groove. That part of the carapace lying between 
them covers the heart. Examine the frontal 
spine or rostrum projecting from the carapace. 
What is its shape ? Size ? Structure ? Color ? 
How fastened to the carapace ? Is it movable ? 
Is it an appendage ? Compare the rostra of sev- 
eral specimens. Turn the animal over on its back. 
What traces of segments do you find on the ven- 
tral side of the cephalothorax ? Are the segments 
movable ? Note the shape of the sterna of these 
segments. Examine the margin of the carapace. 
Does the shape of the margin bear any relation to 
the number of legs % With a pair of forceps or the 
handle of a scalpel raise up this margin, and note 
that a part of it, the branchiostegite, extending 
downward from the branchio-cardiac groove, is 
free from the body. Is this portion comparable to a 
single pleuron or to several fused together ? Why ? 
With a pair of strong scissors cut the branchio- 
stegite away on one side, and note the structure of 
the skin lining the inner surface of the branchio- 
stegite. What outgrowths does the skin bear? 
Note all the differences between the outer and 
inner surface of the branchiostegite. Note the 
cavity, the gill-cavity or branchial chamber, 
covered by the branchiostegite. With a pair of 
strong scissors make a transverse section of the 
cephalothorax just behind the large claws. Care- 
fully pick away the soft parts, or clean thoroughly 
by boiling for five to ten minutes in caustic potash, 
and compare with the third abdominal segment. 
What differences in the shape of the tergum ? Note 
on it the two small prominences or endotergites 
near the middle. In what way is the sternum 



144 THE BIOLOGY OF THE ANIMAL 

modified ? Note the ingrowth or endosternite, 
internal to the bases of the appendage. Do you 
find on the abdominal segments anything corre- 
sponding to the endotergites and endosternites ? 
Do you find any soft parts — e. g., muscles — at- 
tached to the latter? Compare the epimeron 
with that of the abdominal segment. What dif- 
ference in size ? In direction ? Note that it 
forms the inner wall of the branchial chamber, 
and bears an ingrowth or endopleurite. What 
is attached to the latter ? If you regard the 
outer wall of the branchial chamber (branchioste- 
gite) as composed of united pleura, do you like- 
wise regard the inner wall as consisting of fused 
epimera ? Why ? Counting only the sterna, how 
many segments can you find in the cephalotho- 
rax? Do you find a pair of appendages to cor- 
respond to each sternum ? Are the sterna mova- 
ble upon one another ? 

Draw the section of the thorax as seen from the end, 
also from the under side. 

The last section of the abdomen is called 

III. The telson — What is its shape? Color? What 
differences between the tergal and sternal sur- 
faces ? Does it bear any appendages ? Note the 
structure of its margin. Compare it in shape, 
size, and structure with the other sections of the 
abdomen. Is the telson a segment? Note the 
opening (anus) on its under side. Try to find a 
hardened portion, the peri-anal plate, on each 
side. 

C. The appendages. — By cutting through the articular 



LOBSTER OK CRAYFISH 145 

(arthrodial) membrane with a small, sharp scalpel, 
remove each of the appendages from one side of 
the body, beginning at the posterior end. Be 
sure to get the entire appendage. Examine the 
more delicate parts in water. 

a. The abdominal appendages. — Some of these 
have already been examined. Review them and 
study the others, noting in each case the structure, 
shape, size, etc.,- as well as any variations from 
the normal. Note that the stalk (jprotqpodite) 
of each consists of two segments, the basal or 
coxopodite and the distal or basipodite; the 
latter forming the base, to which the other seg- 
ments, the exopodite and endopodite, are articu- 
lated. Notice in every case the variations in the 
structure and shape of each segment, especially 
of the first, second, and sixth appendages. Lay 
each of the appendages, posterior face upward, 
upon a paper and draw them natural size. The 
appendages of the sixth segment form, with the 
telson, the tail-fin. 

h. The thoracic appendages. — Can you show that 
of the appendages on this portion of the body 
two groups may be made — a posterior group, 
consisting of five pairs of large appendages, and 
an anterior group of smaller appendages near 
the mouth ? Examine the last thoracic appendage. 
In which direction does it extend ? Does it bear 
an exopodite? Make out the following segments : 
(1) the protopodite, consisting of coxopodite and 
basipodite ; (2) the endopodite, consisting of is- 
chiopodite, meropodite, carpopodite, propo- 
dite, and dactylopodite. Note the relative 
10 



146 THE BIOLOGY OF THE ANIMAL 

shape and size of each of these segments, and ex- 
amine particularly the manner in which they are 
connected and the direction of motion at each 
joint. Can you find an opening, the male geni- 
tal aperture, in one of the segments? Into 
which of the segments does it open ? 
Draw this appendage. 

Kemove the next appendage, being careful not to 
remove the gill attached to the articular membrane, 
and compare with this. Do you find that it has all of 
the segments named above? Does it extend in the 
same direction as the other ? Notice that it also bears 
two parts not found on the other, a gill and a plate- 
like expansion, the epipodite. Where and how are 
these parts attached ? Notice in female specimen of the 
lobster the opening of the receptive apparatus near 
the base of the coxopodite. Draw. Eemove the second 
from the last appendage and compare with the other two. 
Which does it more closely resemble? Does it bear a 
gill and an epipodite ? Note how the dactylopodite is 
attached to the propodite, forming with the latter a pair 
of pincers or a chela. Look for an opening, the female 
genital pore, in the coxopodite of this appendage. 
Draw. Compare the next appendage with the preced- 
ing, noting all the resemblances and differences. Draw. 
Eemove the great chela or pincers and compare 
with the other appendages, noting especially the great 
size of the segments. Are the two chelae shaped alike? 
If not, do you find on examining a number of specimens 
that the great chela of the right side has certain con- 
stant characters and that of the left also? Are the 
two chelae of the same size? Do you find any ex- 
treme difference in the size of the two chelse on the 
same animal ? If so, how do you explain ? Do you 



LOBSTER OK CRAYFISH 147 

find differences in the teeth on the inside of the jaws of 
the forceps ? Are these teeth fastened into sockets ? 
Note the distribution of hairs along the margin and 
over the surface. Is it different from the other append- 
ages examined? Compare several specimens to see 
whether or not the resemblances and differences are 
constant. Draw. 

Can you give any reasons for considering as homol- 
ogous the paired openings found on the thoracic ap- 
pendages ? Keview the five appendages on the other 
side of the body and note their relative size, the various 
directions in which they extend, the motions allowed 
by their joints, etc. 

Kemove the next appendage in front, the third max- 
illipede or " foot-jaw." Can you find all the. segments 
represented in the great chela? In the last thoracic 
appendage ? Does it have an exopodite ? A gill ? An 
epipoclite ? Note the bunch of bristles, the coxopoditic 
setae. Are they on the coxopodite or epipodite ? Note 
the teeth on this appendage. How many segments 
bear them ? What is their arrangement on each seg- 
ment ? Study the distribution of the hairs. Draw. 
Why is it called a " foot-jaw " ? 

Eemove the next two appendages, the second and 
the first maxillipedes, and compare with the preced- 
ing. Do you find any segments lacking? Which are 
especially modified and how ? Draw each. 

Review all of the thoracic appendages and notice 
again that they naturally fall into two groups. Give 
what you consider to be the most characteristic struct- 
ural features of each group. On what grounds do you 
divide them ? 

c. The head appendages.— Remove the most poste- 



148 THE BIOLOGY OF THE ANIMAL 

rior, the second maxilla. What segments are 
lacking on this appendage? What peculiar modi- 
fication of the coxopodite and basipodite do you 
find? Did you find anything similar on the other 
appendages? Note the large plate-like expansion 
or scaphognathite. To what is it fastened ? To 
what does it correspond on other appendages? 
What is its position in the gill-chamber? Draw. 
Kemove the next appendage, the first maxilla, and 
compare with the preceding. Draw. 

The next appendage towards the front is the man- 
dible or jaw. Kemove this and examine the structure 
of the protopodite. What is the position of the teeth ? 
How many are there ? Is the number the same on the 
other mandible ? Note the palpus, which here repre- 
sents the endopodite. What segments are lacking? No- 
tice lying just back of the mandible a thin, plate-like ex- 
j)ansion, the metastoma, and in front, another shield- 
shaped piece, the labrum. What is their relation to 
the mouth opening ? What is their structure ? Are 
they appendages ? Why ? Draw the mandible, meta- 
stoma, and labrum. 

Note the opening of the mouth, its shape and size. 
Notice also that it opens directly upward. 

Kemove the next two appendages, the antenna and 
the antennule. Examine the first. What segments can 
you find ? Note the long feeler. Which segment does 
it represent? How many joints has it? Is it hollow 
or solid? What is its range of motion? Note the 
tubercle on the lower side of the coxopodite. What is 
its color ? Note the opening. Draw. Are these open- 
ings in the antennae, the openings of ducts of the 
"green gland" homologous with those on the thoracic 
appendages ? Why ? 



LOBSTER OR CRAYFISH 149 

Compare the antennule with the antenna. How does 
the protopodite of the former differ from that the of 
latter? On the basal joint look for the opening of the 
auditory organ. Note the distribution of setse. Ex- 
amine the two feelers. "Which segment do they repre- 
sent ? Compare with the large one. Draw. 

The most anterior of the cephalic appendages (?) is 
the eye-stalk or ophthalmite. What segments can 
you find in it ? Draw. 

Go over all of the appendages again. Can you make 
out that they are all constructed upon the same funda- 
mental plan, i. <?., that the appendages are homologous ? 
What would you consider to be the structure of a typical 
appendage? Divide the appendages into such groups 
as you think their structure warrants. How many 
groups do you make? Do the groups gradually shade 
into one another structurally? In each group, what 
is the most important modification of the typical seg- 
ment? If the morphological rule that each pair of 
appendages corresponds to a segment be correct, how 
many segments are there in the body of the animal ? 
How many are plainly visible ? How many are " con- 
solidated " ? In what regions are they most plainly 
seen ? How many are there in each region ? In which 
region is consolidation carried to the greatest extent ? 
Note the abrupt bend, the cephalic flexure, which is 
made by that part of the body anterior to the mouth. 
As regards segmentation of the body and appendages, 
how do the lobster and crayfish compare with the earth- 
worm ? How as regards cephalization, i. <?., the ten- 
dency to consolidate the mouth parts, eyes, ears, brain, 
etc., into a distinct head-region? 

D. The gill-chamber.— Between what parts of the 



150 THE BIOLOGY OF THE ANIMAL 

body does it lie? What separates the branchial 
cavity from the body-cavity ? At which point does 
it communicate with the exterior ? Look for the 
cervical canal, in which lies the scaphognathite. 
Does the branchial cavity contain any organs 
besides gills ? Notice that the gills may be divid- 
ed into three groups: (1) podobranchiae, those 
attached to the exopodites of the appendages; 
(2) arthrobranchiae, attached to the articular 
membranes ; and (3) pleurobranchiae, attached 
to the inner wall of the branchial chamber. 

Eeview all of the appendages and note those 
on which you found gills. How many arthro- 
branchiae do you find? Do you ever find two 
on the same membrane? If so, on which? 
What position have the arthrobranchiae with 
reference to those attached to the appendages ? 
How many pleurobranchiae are there? What 
is their position ? In which group are the gills 
largest ? Do any of them branch ? Do all have 
the same general shape ? Are the gills within 
the body? Eemove in succession one of the 
largest gills of each group, place it in a dish of 
water, and examine its structure. Is the gill stiff 
or flexible ? Do all have the same structure ? 
If not, which are the most complicated ? Notice 
the finest divisions, the branchial filaments, of 
the gill. In the crayfish, note that some of the 
pleurobranchiae are rudimentary. Can you give 
reasons for calling them " rudimentary " ? 
Draw a gill of each kind. 

K The exoskeleton or cuticle. — What is its nature? 
Color? Thickness? Is it the same on the ap- 



LOBSTER OE CEATFISH 151 

pendages as on the body ? How is it modified 
at the joints? Does it bear any outgrowths? 
If so, where are they and what is their structure ? 
Put a piece of the exoskeleton into boiling water 
for a few minutes. What changes take place in 
it? Put a piece into dilute hydrochloric acid, 
consisting of one part acid to four parts water. 
What happens? Explain. 

F. The organs of special sense. 

a. The tactile organs — i. e., the antennas, the anten- 

nules, and the palpi on the oral appendages — 
have already been studied. 

b. The eye. — Remove one of the eye stalks, note again 

its gross structure, then examine with a lens. 
Notice its transparent outer covering, the cor- 
nea. What is its shape? How is the surface 
marked ? Each area or facet corresponds to one 
of the elements of which the compound eye is 
composed. What is their shape ? Arrangement? 
Estimate the number of facets. Make a longi- 
tudinal section of the eye and its stalk, cutting 
the hardened portion with scissors, the rest with 
a scalpel. Examine with a strong lens or the 
low power. Note the edge of the cornea; the 
ring of opaque exoskeleton to which it is con- 
nected by a membrane ; the striated mass marked 
by radiating lines, indicating the striated spin- 
dles and the crystalline cones; the dark-col- 
ored central mass; the optic ganglion, from 
which runs through the axis of the stalk; the 
optic nerve, and the muscles lying on each 
side of the optic nerve. Examine as closely as 



152 THE BIOLOGY OF THE ANIMAL 



possible the relative position of these various 
parts, and make a drawing of the eye. 

c. The ear. — Among the bunches of setse on the basal 

joint of an antennule find, by using a fine bristle, 
the opening into the auditory organ. Leave the 
bristle inserted and, using it as a guide, cut away 
the under side of the joint with a scalpel. Close 
examination will reveal a small transparent sac, 
the auditory sac, lying among the muscles with- 
in the joint. Dissect this out. How large is it ? 
Examine under the low power in a drop of water 
or glycerine. What is the shape of the sac? 
Color ? Cut it open. Do you find sand-like par- 
ticles or otoliths inside? Notice also the seta? 
or auditory hairs. What is their position? 
Shape ? Kelation to the otoliths % 
Draw the sac, otoliths, and seta3. 

d. The olfactory setae. — Examine with the lens the 

under surface of each joint of the endopodite of 
the antennule for setae. Are these at all different 
from those found at the edges of the segments? 
Draw. 

Internal Anatomy. — The various systems are given in 
the order in which they are most conveniently examined. 
Take a second specimen, and with a pair of strong shears, 
being careful not to injure the organs lying beneath, cut 
through the exoskeleton along each side of the body 
from the telson to the rostrum. Begin at the anterior 
end of the abdomen and, working back, carefully remove 
the upper half of the shell by cutting the muscles with 
a sharp scalpel at their points of attachment, noting par- 



LOBSTER OR CKAYFISH 153 

ticularly the position of these points. Use an injected 
specimen if obtainable. 
Lying beneath the shell look for 

A. The epidermis or " hypodermis." — Do you find 
it everywhere inside the skeleton ? What is its 
color? Is it more closely attached to the seg- 
ments of the shell at some points than at others ? 
If so, where are these points ? 
Eemove the epidermis. 

B. — The Muscular System. 
Lying one on each side of the median dorsal line find 

a. The extensor abdominis muscles. — Trace the 

two strands forward to the thorax. What is 
their color ? Shape ? Where do they arise ? To 
what are they attached posteriorly ? JSTotice that 
each is made up of smaller strands, and that 
these strands are attached to the terga of the 
segments. Are the two strands connected in 
any way ? Are the muscle fibres attached to the 
epidermis or to the exoskeleton? When these 
muscles contract, what motion do they produce ? 

Remove the extensor abdominis muscles. 

Arising on the side of the carapace, directly 
above the origin of the extensor abdominis, are 

b. The levator abdominis muscles. — In what di- 

rection do these muscles run ? To what are their 
posterior ends fastened? What relation as re- 
gards position do these muscles bear to a ? How 
do thejr compare with a in shape and size ? What 
motion do they produce ? 

c. The flexor abdominis muscle. — The greater 



154 THE BIOLOGY OF THE ANIMAL 

part of the abdomen will now be seen to be filled 
with a mass of muscle, through the middle of 
which runs a deep groove. In the groove are the 
superior abdominal artery with its side branches 
and the intestine. With scissors divide the 
branches of the blood-vessel as far out at the 
side as possible, cut the intestine across just in 
front of its dilated end, and lay both blood-vessel 
and intestine over at one side. Turn forward 
the glands and other organs covering the ante- 
rior end of the muscle. Cut vertically through 
the mass of muscle at the line of junction of the 
fifth and sixth segments, and carefully work it 
out of the shell, taking precautions not seriously 
to injure the nerves lying below the muscle. 

How does it compare in size with a and h% 
Of how many smaller masses is the muscle com- 
posed ? In what direction do its fibres run ? To 
what part of the segments are they attached ? 
Do the fibres extend into the pleural region of 
each segment ? To what is the anterior end of 
the muscle attached? For what purpose is the 
deep median groove? What motion does the 
muscle produce ? How do you account for its 
size? 

d. The adductor muscle of the mandible. — Lay 

the carapace back on the body, note the position 
of the cervical groove, and look directly in front 
of it on the inside for the origin of a fan-shaped 
muscle, which tapers to a tendon and runs ob- 
liquely downward to the mandible. Note the 
direction of the muscle. Compare the length of 
the muscular portion with that of the tendinous 



LOBSTER OR CRAYFISH 155 

portion. Does the tendinous portion branch? If 
so, to what is the branch attached? To what 
part of the mandible is it attached ? Pull on the 
muscle and notice the movement of the mandible. 

e. The antexmary and other muscles. — Examine 
the basal joints of the antennae, antennules, and 
ophthalmites, and note, the small muscle strands 
running from the joints to adjacent portions of 
the exoskeleton. With fine-pointed scissors split 
these organs open lengthwise. Do the muscles 
extend into these appendages ? 

/. The muscles of the great chela.— With a scal- 
pel cut through the articular membrane at the 
base of this appendage and remove it entire. 
Notice that the muscles of the basal joints are 
attached to ingrowths of the sternum, the endo- 
sternites. With a pair of bone forceps cut 
around the edges of the propodite and the dac- 
tylopodite and remove the shell. Do the muscles 
entirely fill these segments ? With a scalpel make 
a vertical cut, about half the thickness of the 
muscle, running from the angle between these 
two segments to the outer corner of the base of 
the propodite, and remove the inner half of the 
muscle which is thus divided. Notice the cen- 
tral tendon. How do the muscle fibres in the 
propodite run with relation to this tendon ? Ee- 
move the remainder of the muscle mass, thus ex- 
posing the entire upper surface of the tendon. 
What is its shape? Size? With a pair of for- 
ceps grasp the posterior border of the tendon 
and pull upon it. To what is it connected at its 
outer end ? What motion does it produce ? Can 



156 THE BIOLOGY OF THE ANIMAL 

you explain its large size and the connection to it 
of so many muscle fibres? Why should this be 
called the adductor muscle ? On the inner side 
of the base of the propodite find another tendon 
to which are attached muscle strands. Compare 
this tendon and muscle in all respects with the 
first, and give reasons for the differences found. 
Why is this muscle called the abductor ? Notice 
that each tendon is an ingrowth of the exoskele- 
ton at the base of the dactylopodite. 

Peel what is left of the muscle mass out of the 
two segments, leaving the epidermis attached to 
the exoskeleton, and note the honeycomb appear- 
ance of the epidermis, especially near the base of 
the propodite. What causes this appearance ? 

g. The microscopic structure of muscle. — From 
a recently killed specimen take a small piece of 
muscle, lay it on a slide in a drop of normal salt 
solution, tease the muscle carefully with fine- 
pointed needles, and examine under the low, then 
the high power. What is the structure of a mus- 
cle strand ? Of one of the constituent fibres ? 
Are the fibres striated ? Draw. 

Stain in dilute acetic acid carmine and note 
the results. 

C. — The Circulatory System. 

Lying at the anterior end of the superior abdominal 
artery look for 

a. The pericardial sinus. — What is the shape of 
the sinus ? With scissors divide it along the me- 
dian dorsal line, and carefully fold back the flaps 
thus made. What is the nature of its wall? Look 



LOBSTER OR CRAYFISH 157 

for the openings where the blood-vessels coming 
from the gills enter the pericardial sinus. Lying 
within the sinus will be found 

h. The heart. — What is its shape? Its size as com- 
pared with the sinus ? Look for the fine thread- 
like muscles, the alary muscles, extending from 
the corners of the heart to the wall of the sinus. 
How many such muscles do you find? On the 
upper surface look for the two dorsal cardiac 
apertures. What is their position ? Shape ? 
Size ? Can you detect the lip-like valves guard- 
ing the openings ? Remove the roof with scissors. 
What is the structure of the wall of the heart ? Is 
the cavity single, or is it divided into chambers, 
as auricles and ventricles ? On the floor of the 
heart look for the ventral apertures. How 
many do you find ? What is their position ? Do 
they have valves ? Compare in all respects with 
the dorsal apertures. . On the sides of the heart 
look for lateral apertures. How many are 
there? What is their position? Compare with 
the other apertures. Cut away one side of the 
heart down to the level of an aperture, and try 
to see how the valves work. Do they prevent 
the exit or the entrance of the blood at these 
apertures ? 

Make a drawing of the heart, showing on one side 
the dorsal surface, on the other the internal aspect. 

Running from the posterior end of the heart 
find 

c. The superior abdominal artery. — How far does 
it extend ? Notice the branches. At what points 
are they given off? To what parts do they run? 



158 THE BIOLOGY OF THE ANIMAL 

How does their number compare with that of the 
abdominal segments ? Does it send any branches 
to the intestine ? 

Originating at the anterior end of the heart 
find 

d. The ophthalmic artery. — How does it compare 

in size with c ? Trace it forward over the 
stomach. Does the artery give off branches ? 
If so, where do they go ? 

Branching out from the heart, one on each side 
of the ophthalmic artery, find 

e. The antennary arteries. — What course does 

each follow? What is their relation to the ad- 
ductor muscle of the mandible ? To the stomach ? 
Do you find the branch (gastric artery) given 
off by each ? Can you find branches running to 
the kidney or "green gland," antennae, anten- 
nules, and rostrum ? Do you find any branches 
running to the muscles around the stomach ? 

At the ventral side at the anterior end of the 
heart find 

f. The hepatic arteries. — How many are there ? 

Can you trace their course ? How do they com-- 
pare in size and length with e ? 

Arising at the posterior end of the heart, im- 
mediately below the superior abdominal artery, 
find 

q. The sternal artery. — In what direction does it 
run? On which side of the intestine does it pass ? 
Notice that it divides into two branches, one of 
which, the antero- ventral artery, runs forward 
(its course should not be traced until the organs 



LOBSTEE OR CRAYFISH 159 

lying in the cephalothorax have been examined 
and removed) ; the other, the inferior abdomi- 
nal artery, runs backward. What is the relation 
of the latter to the ventral nerve-chain ? 
Make an outline drawing of the body of the animal 

seen in vertical longitudinal section, and indicate the 

course of the blood-vessels examined. 

h. The microscopic examination of the blood. — 

Kill a specimen, make an opening through the 
shell into the pericardium, put on a slide a drop 
of the fluid which escapes, and examine. "What is 
the color of the blood ? Does it coagulate readily ? 
What sort of corpuscles does it contain ? Draw. 

D. — The Digestive System. 

Remove all of the gills, glands, etc., on one side of the 
thoracic region so as to give a side-view of 

a. The stomach (lying immediately in front of the 
heart). — What is the shape of its upper surface ? 
Notice the muscle bands running in various direc- 
tions. Endeavor to make out a pair, the ante- 
rior gastric muscles, passing from the anterior 
end of the roof of the stomach to the base, the 
procephalic process, of the rostrum. What 
motion do these muscles produce ? Another 
pair, the posterior gastric muscles, pass from 
the roof of the posterior end of the stomach to 
the carapace and end just in front of the cervical 
groove. Draw the upper surface, showing the 
attachments of these muscles. Another large 
sheet of muscle fibres, the great constrictor, 
surrounds the posterior end on the ventral side. 
Notice that some portions of the wall of the 



160 THE BIOLOGY OF THE ANIMAL 

stomach are hard and firm, while others are more 
flexible. What relation exists between the mus- 
cles and the hardened portions of the stomach 
wall? Carefully remove the stomach from the 
surrounding parts, cutting off the entrance, or 
oesophagus, close to the mouth, and leaving 
about an inch of the intestine attached. What 
is the position of the stomach with regard to the 
mouth ? Lay the stomach on its side in a dish of 
water or fifty per cent, alcohol, and remove all 
of the superfluous parts. Do you find that the 
wall consists of two layers ? To which of these 
are the muscles attached? In which do the 
hardened portions lie ? Does the outer fit closely 
over the inner coat ? What is the shape of the 
stomach when seen sidewise? Draw. Examine 
the oesophagus or gullet. How long is it ? How 
wide ? Are its walls flexible or rigid ? At what 
point does it enter the stomach ? . Can it be di- 
lated ? Is its lining continuous with the outer 
covering of the body ? Note the two regions of 
the stomach proper, the anterior or cardiac re- 
gion and the posterior or pyloric region. How 
do they compare in size ? If collapsed, the stom- 
ach may be distended by injecting w T ater into the 
oesophagus. What difference in shape ? 

Note the lining of the stomach. Of what is it 
composed? Trace it to the mouth. Eemove a 
portion of the roof and front wall of the stomach, 
so as to expose the interior, being careful not to 
cut away any of the hardened portions or ossi- 
cles. Examine the ossicles and try to make out 
the following, studying in each case the position, 
shape, size, and attachments : 



LOBSTER OK CRAYFISH 161 

1. The cardiac ossicle, extending across roof of 

cardiac cavity. 

2. The pyloric ossicle, extending across roof of 

pyloric cavity. 

3. The lateral cardiac ossicles, attached to ends 

of 1. 

4. The lateral pyloric ossicles, attached to ends 

of 2. 

5. The iiro - cardiac ossicle, passing backward 

from 1. 

6. The prepyloric ossicle, passing backward and 

downward from 2. 

7. The gastrolith, in the anterior cardiac wall. If 

this is not found, see if there is not a thicken- 
ing of the cuticle in this region. 

Divide the stomach accurately along the 
middle line with a pair of scissors, and look for 

8. The postero- ventral ossicles, in the posterior 

wall of the cardiac sac. Do you find any other 
ossicles than those mentioned ? 
Make a drawing of the framework formed by the 
ossicles. 

Look also for 
h. The gastric teeth. 

1. The median tooth (lying between the ends of 

the two median ossicles). — What is its shape \ 
Size % Color ? Does its tip touch against any 
other part ? 

2. The lateral teeth (attached to the lateral py- 

loric ossicles). — Compare with 1. 

Gently pull upon the cardiac and pyloric 
ossicles in such a way as to imitate the action 
of the muscles attached to these parts. What 
motion do the teeth make % 

11 



162 THE BIOLOGY OF THE ANIMAL 

Examine the opening between the cardiac and 
pyloric portions of the stomach guarded by the 
median cardio - pyloric valve. How is it 
formed ? "What is the nature of its surface ? 
Which way does it open ? Do you find other 
valves, the lateral cardio - pyloric valves? 
If so, compare with the median valve. Note 
the opening into the intestine. Is it also guard- 
ed by valves and setaB ? 

c. The intestine. — If necessary, distend the intestine 

with water injected with a pipette into the anus. 
What is its general direction through the body ? 
At what point does it leave the stomach ? What 
is its length? How is it held in place? On the 
dorsal surface of the intestine, near the posterior 
end, find a sac-shaped outgrowth, the coecum. 
How does it compare with the intestine in diam- 
eter? Split the intestine open by a cut made 
lengthwise along the dorsal surface from the 
anus to the pyloric portion of the stomach. Is 
the intestine wrinkled or folded? If so, in what 
direction? Is the lining membrane anterior to 
the coecum similar to that posterior to the same 
part ? Is that part posterior to the coecum con- 
tinuous with the exoskeleton ? Compare with the 
lining membrane of the stomach. 

Find a lobulated mass lying on each side of the 
stomach, 

d. The digestive glands or "liver." — How much 

of the cephalothorax does it occupy? What is 
its color ? Look for the duct by means of which 
the gland connects with the intestine. Where 
does the duct enter the intestine ? 



LOBSTER OR CRAYFISH 163 

E — The Excretory System. 

Lying in the lower side of the head will be found 

a. The " green glands" or kidneys. — What is their 

position with reference to the mouth ? How do 
they compare in size and color with the digestive 
glands ? Is there any similarity in the general 
structure of the two kinds of gland ? 

Leading from the green glands to the base of 
the antennae find 

b. The ureters. — What is their shape? Length? 

Pass a bristle into the opening in the tubercle on 
the base of the antenna. Does the bristle enter 
a ureter ? 

F. — The Reproductive System. 
In the male find 

a. The testes (in the lobster, two tubular organs ex- 
tending from the lateral angles of the stomach 
back into the abdomen ; in the crayfish, an organ 
bilobed anteriorly, but with a single lobe poste- 
riorly). — How far back do they extend ? What 
is their color? What is their position with re- 
gard to the intestine ? To the heart ? What 
holds them in position? Are the two organs 
connected at any point ? 

Cut into one of the testes of a recently killed 
specimen, £lace a drop of the contained fluid upon 
a slide, and examine with a high power. Exam- 
ine the shape and general appearance of the 
sperm -cells or spermatozoa. Do they move? 
Draw some of these cells. 

Leading from the testes find two tubes, 



164 THE BIOLOGY OF THE ANIMAL 

b. The vasa deferentia. — What is their shape? Size ? 

In which direction do they run ? Where do they 
open ? 

In the female find in a position and of a shape 
quite similar to the testes, 

c. The ovaries. — Compare in every respect with the 

testes. If the ovaries contain eggs, examine them 
in different portions of each gland to see if there 
is any difference in size. Make a longitudinal 
cut into the ovary, wash with a gentle stream of 
water, and then look for the ovisacs, in which 
the eggs are contained. Examine under a lens. 
Place some of the eggs on a slide, stain with ma- 
genta, and examine. Draw. 
Find also 

d. The oviducts. — Compare these with the vasa 

deferentia. 

Remove the muscles and digestive organs from 
the specimen, also the endophragmal system 
(a complicated set of ingrowths from the cuticle 
of the ventral surface), and study the principal 
portions of 

G. The Nervous System. 

At the base of the rostrum look for 

a. The supra-cesophageal ganglia or " brain." — 

What is their shape ? Are they connected with 
each other ? Do the}^ give off any branches ? If 
so, where do these branches run? Look for 
nerves passing from the " brain " to the eyes, an- 
tennules, and antennse. 
Behind the gullet find 



LOBSTER OR CRAYFISH 165 

h. The sub-oesophageal ganglion. — Compare with 
a in shape and size. 

Is there any connection between the ganglion 
and the "brain"? 

c. The thoracic ganglia. — How many are there ? 

How are they situated ? Are they connected with 
one another ? How do they compare in shape 
and size with a and o ? How many in each seg- 
ment % To what parts do their branches run ? 

d. The abdominal ganglia. — Compare in all re- 

spects with a, h, and e. 
Make a diagram showing the shape and relation of 
those parts of the nervous system mentioned above, 

physiology 

The living animals should be studied in a pan of 
water or in an aquarium. Though living specimens are 
preferable, it will be possible to do much of the follow- 
ing work upon the dead animal. 

a. Movements. — Can the animal walk? If so, in how 
many different directions ? At how rapid 'a rate? 
What appendages are used for this purpose ? Do 
all of these appendages move in the same man- 
ner? Do all occur on the same region of the 
body ? Can you give any reason why they 
should be here? Do all seem to be adapted to 
this particular function? Does the animal swim? 
By means of what organs ? Where are these lo- 
cated? Why are they here? How do they 
work ? In what direction does the animal swim ? 
Why in this direction? Does it use both am- 
bulatory and swimming organs at the same time ? 



166 THE BIOLOGY OF THE ANIMAL 

How rapidly can it SAvim? Has it any other 
modes of locomotion than walking and swim- 
ming ? Is its body adapted for rapid motions ? 
For walking and swimming long distances ? 

1. Movements of the regions of the body. — What re- 

gion of the body is most flexible? In what 
direction does it bend ? To what extent can it 
bend in this direction ? Of what use is this 
motion ? Can it bend in the opposite direction ? 
Why? 

2. Movements of the appendages. — Examine each 

appendage separately. What motions have 
the abdominal appendages ? Do all have the 
same ? Is their range of movement very great ? 
Of what use are their movements ? 

Of what movements are the last five cephalo- 
thoracic appendages capable? Can you de- 
scribe a circle with their tips ? By what sort 
of joint are their segments connected ? How 
is it possible with this kind of joint to produce 
the range of motion possessed by these append- 
ages ? Notice the peg-shaped outgrowth upon 
* one of the basal joints of the chelae. Wha.t is 
its use ? Study the movements of the dactylo- 
podites. For what purposes are the various 
forceps used? What are the motions of the 
maxillipedes and the maxillae ? Is there any 
advantage in this ? Turn the animal over on 
its back. How does it right itself ? What ap- 
pendages are used ? 

What difference between the lobster's jaws 
and yours in their direction of motion ? 

In what different directions can the antennae 
point ? The antennules ? In what position are 



LOBSTER OK CRAYFISH 167 

the former usually carried ? In what the lat- 
ter ? What advantages arise from these move- 
ments ? Is the scale-like appendage of the an- 
tenna mobile ? Examine the eyes. How great 
is their range of motion ? Can the lobster look 
backward? Down by its side? Upward? Can 
it see what it is eating ? Can it close its eyes? 
Are any of the movements such as to protect 
the eyes? 

Watch for the motions of the scaphognathite. 
In what manner does it move ? At what rate ? 
Of what use are its movements ? Can you 
make out whether or not the gills move? 
Does the branchiostegite ? 

Feeding. — If the lobster is studied, put small pieces 
of meat, clam, bread, sea-weed, etc., in the aqua- 
rium ; if the crayfish, use meat and bread. If 
not too large, put the animal into a glass dish, so 
that by holding it up you can see the motions of 
the mouth parts. How does the animal seize its 
food ? How convey it to the mouth ? While 
eating one piece will it seize another? Attempt 
to remove a piece which the animal is holding. 
What does it do? What is the action of the 
chela? ? Of the maxillipedes ? Of the maxilla? ? 
Is the food thoroughly chewed before being swal- 
lowed ? Does the animal " wash down " its food 
with a swallow of water ? 

Examine again the stomach of a dead specimen 
in water and try to discover the action of the 
various gastric ossicles, and how their action 
supplements the work of the jaws. After food 
has once been swallowed, what prevents it from 



168 THE BIOLOGY OF THE ANIMAL 

dropping out of the mouth again when the next 
mouthful is swallowed ? Do you find any struct- 
ures whose function may be to separate the larger, 
undigested particles of food and prevent their en- 
trance into the intestine ? 

Are the lobster and the crayfish structurally 
adapted to capture living animals for food ? Is 
either adapted for catching as prey animals hav- 
ing quick, active movements ? 

If living specimens cannot be obtained, examine 
the contents of the stomachs of dead ones. 

c. Breathing. — Place the animal in a dish of water and 
allow it to become quiet. Then with a pipette run 
into the water, close to the bases of the hinder 
thoracic appendages, a few drops of water con- 
taining particles of indigo, carmine, or India ink. 
Note the direction of the current. Do the parti- 
cles enter the branchial chamber ? If so, at what 
place ? Where do they come out ? To discover 
the cause of this current, with a pair of strong 
scissors open the cervical canal by making two 
cuts : the first directly behind the cervical groove, 
the second about a half -inch in the lobster, or 
one-fourth inch in the crayfish, back of the first 
and parallel to it. Then remove that part of the 
branchiostegite included between the cuts. This 
operation can be done with little or no incon- 
venience to the animal, and permits the action of 
the scaphognathite to be seen. Watch the mo- 
tions of the last. How does it cause a flow of 
water over the gills? Examine a specimen in 
which the legs are still attached to the thorax. 
Move one of the legs. Does the gill or podo- 



LOBSTER OK CRAYFISH 169 

branchia move with it? Do you think the po- 
dobranchiae are moved when the animal walks ? 
Can you discover that the epipodites have any 
function ? 

d. Nervous properties. 

1. Touch. — With a long bristle gently touch the 

animal in the following places, noticing each 
• time whether or not, by moving or otherwise, 
it gives evidence of feeling the touch : The 
dorsal surface of the carapace, the dorsal sur- 
face of the various abdominal segments, the 
telson, the lower edge of the branchiostegite, 
the hairs on the various appendages of the 
thorax, any of the mouth parts within reach, 
various points from the tip to the base of the 
antennge, likewise of the antennules, the stalk 
and the surface of the eye, and the rostrum. 
Is the sense of touch distributed over the 
entire surface of the body ? Are there any 
appendages which are especially sensitive to 
touch ? If so, can you give any reasons for 
this % Do the hairs on various parts of the 
body show different degrees of sensibility to 
touch ? Are any of them so sensitive as to 
warrant regarding them as " tactile hairs " ? If 
so, where are they and why should they be so 
situated ? 

2. Taste. — Put a piece of bread and a piece of meat 

in the water near the animal. Does it show 
any preference for either of these ? Try a piece 
of fresh and a piece of decaying meat. Which 
does the animal prefer ? 

3. Smell. — Lay a piece of meat in the bottom of a 



170 THE BIOLOGY OF THE ANIMAL 

dish containing a live lobster or crayfish which 
has had nothing to eat for three or four days, 
and, at some distance from the animal, with a 
pipette quietly force a current of water from 
the meat towards the animal. Does the latter 
show by its actions that it is conscious of the 
presence of the meat ? How does the animal 
behave ? Do you notice any peculiar motions 
of the antennae or antennules ? How long be- 
fore it recognizes the presence of the meat ? 
Can you decide definitely whether its actions 
are due to the sense of smell or that of taste ? 
4. Sight. — Find a specimen which is lying quietly 
near the side of the aquarium. Move your 
hand quickly past the animal. Is it at all 
disturbed? Watch several which are moving 
around. Do any of them show that they can 
see the others coming from a distance ? Do 
the eye-stalks move in such a manner as to per- 
mit the animal to look in different directions ? 

General Questions. — Considering the appendages mor- 
phologically, in what various ways do you find segments' 
of the typical appendages modified ? Examine again 
all of the appendages, and write a list of the modifica- 
tions of structure found on each. From this list make 
another, giving all of the variations found. Is any one 
segment more susceptible to variation than the others % 
If so, can you give any reasons for it ? 

Eeview all of the appendages from a physiological 
rather than a morphological point of view. Examine 
each appendage by itself, and write out a list of all the 
functions which you know each appendage to be capable 
of performing. Then from this list make a second, 



LOBSTER OR CRAYFISH 1*71 

showing the various functions which a typical append- 
age, though modified in different ways, may perform. 
Do you find here a close relationship between structure 
and function \ Can you determine whether the struct- 
ure of an organ determines the function which it can 
perform, or vice versa ? 

What means of protection from its enemies has the 
animal ? What means of defence ? Of offence ? When 
the animal is moving along, does it co-ordinate the move- 
ments of its various appendages — i. <?., do all of the ap- 
pendages work together for the accomplishment of a 
certain object ? Turn a live specimen over on its back. 
In righting- itself, does the animal show co-ordinated 
motions of the appendages ? 

Compare the lobster or the crayfish w T ith the earth- 
worm as regards the plan upon which the body is con- 
structed, the collection of the segments or metameres 
into well-defined regions, the arrangement and structure 
of the appendages, the number, position, and structure 
of the sense organs, the structure of the muscular, the 
nervous, and the digestive systems, etc. Which is the 
more complicated or " higher " animal ? Why ? 

Use the crab {Cancer or Callinectes) for comparison. 






Locust ( Caloptenus Sp.) 

Material. — Locusts, generally miscalled " grasshop- 
pers," may be found in greater or less abundance in fields 
and along roadsides, from midsummer until the early 
frosts come. The largest specimens available should be 
caught. Each student should have two or three speci- 
mens of each sex. If this type is to be studied at a time 
of year when living insects cannot be obtained, a suffi- 
cient number of them should be preserved in alcohol. 
They may be put when first caught into three to six 
times their bulk of sixty per cent, alcohol for a day, and 
then transferred to about the same quantity of eighty 
per cent, to ninety per cent, for keeping. 

It is impracticable to try to keep these insects alive 
during the winter. 

For the examination the student will need fine for- 
ceps, small scalpel, fine scissors, hand -lens, dissecting- 
needles, chloroform or ammonia, fifty per cent, alcohol, 
metric scale, compound microscope, dilute hydrochloric 
acid, and normal salt solution. 

Method of Examination. — Preserved specimens may 
be studied without any further preparation. It is well, 
however, to remove them from the strong alcohol in 
which they are kept to a mixture of equal parts of fifty 
per cent, alcohol and glycerine for about an hour before 
beginning the examination. The stiffened muscles be- 



' — — "— c 



LOCUST IV 3 

come flexible and the drying of the specimen is pre- 
vented by the glycerine. 

Let the student lay the specimen before him on the 
table with the back uppermost and the head turned 
away from him, and make out as many as possible of 
the characters. Then the body may be studied in dif- 
ferent positions, the appendages removed and examined, 
longitudinal and transverse sections made, etc. 

Specimens may be killed by pouring a few drops of 
chloroform, ether, or ammonia on the body. 

Living specimens may be placed for study in glass 
jars or fruit-cans, into which a few blades of fresh grass 
have been thrown. 

MORPHOLOGY 

a. The shape of the body as a whole. — What is the gen- 
eral shape? Does it resemble that of the cray- 
fish or lobster ? Is the body bilaterally symmet- 
rical ? Is the insect's shape at all related to its 
mode of life ? How many regions are there in the 
body? Compare with lobster and crayfish. How 
distinguished from one another ? Are they more 
or less plainly marked off from one another than 
in the lobster or crayfish ? Do all of them bear 
appendages ? Compare with crayfish. How many 
pairs of appendages do you find? How many 
kinds of appendages are there ? What character 
have the appendages in common ? Is there an ex- 
oskeleton? If so, does it in any way resemble the 
lobster's ? How many segments or indications of 
such are to be found, without dissection, in each 
region ? Compare with lobster. How long is 
your specimen? Measure several specimens to 



174 THE BIOLOGY OF THE ANIMAL 

find the average size. How many colors do you 
find on the body ? How are they distributed ? 

b. The head. — What is its shape as seen from the front ? 
From the side? From above? How is it con- 
nected to the thorax ? Is there a movable neck ? 
How many pairs of appendages does it bear ? 
On the head find 

1. The compound eyes. — How many? How sit- 

uated ? Are they upon eye-stalks ? Compare 
with crayfish. What is their color ? Shape ? 
Size ? Examine with a hand-lens. Estimate 
the number of facets in the eye. What is the 
shape of the facets ? Examine the compound 
eye as an opaque object, under the low power. 

2. The ocelli or simple eyes. — How many? How 

situated ? Color ? Shape ? Size ? Compare in 
all respects with the compound eyes. 

3. The antennae. — Number ? Position ? Struct- 

ure ? Color ? Shape ? Size ? Compare with 
crayfish. How do you account for the differ- 
ence in the length of the antennae of the two 
animals ? Examine with a hand-lens and count 
the joints. Examine several specimens to see 
if the number is constant. Are there any varia- 
tions in the size of the joints ? Are the anten- 
nas true appendages ? Why ? Are the anten- 
nas of the locust homologous with those of the 
lobster ? 

4. Cephalic plates. 

Make out the following plates composing the 
head : 
The top and front of the head are formed by 
(a) The epicranium. — What is its shape ? What 



LOCUST 1 75 

proportion of the head does it cover ? What 
is its color? Note the central ridge with a 
simple eye or ocellus in the middle line. 

Fastened to the lower edge of the epicra- 
nium is 

(b) The clypeus. — How does it compare in size 
with the latter? Does it consist of a single 
piece ? Does it bear any ridges ? 

(c) The genae or "cheeks." — Which of the 
above structures do they touch at their edges ? 
What is their shape ? 

Below the clypeus is 

(d) The labrum or "upper lip." — Eaise it up 
with the point of a pin. To what is it attached ? 
What is its shape ? What range of motion has 
it ? Draw: 

5. Mouth parts. 

As was done with lobster or crayfish, remove 
and study also the following 

(a) The labrum (already examined). 

(b) The labium or " under lip." — Compare in 
every respect with the labrum. Does it look 
as though it were made of two parts which had 
fused together along the middle line ? Try to 
make out the following parts : the submen- 
tum, composed of two protopodites fused to- 
gether, the hinder curved portion forming the 
gula; the mentum, which is the fused distal 
joints of the protopodites and bears the endo- 
podites, which together form the ligula; the 
palpi supported on a stump-like base or palpi- 
ger and representing the exopodites. 

(c) The labial palpi. — How many? Where and 
how are they attached to the labium ? Are 



176 THE BIOLOGY OF THE ANIMAL 

they movable ? Of how many joints does each 
consist ? Are the palpi appendages ? Draw 
the labium with its palps attached. 

(d) The maxillae or " soft jaws." — Number? 
Position? Does a maxilla in any respect re- 
semble the corresponding part of the lobster? 
See if you can find the protopodite consisting 
of cardo and stipes, the endopodite consist- 
ing of the lacinia and the galea. What is 
the exopodite ? 

(e) The maxillary palpi. — Compare these in 
every respect with the labial palpi, and draw a 
maxilla with its palp. 

(f) The mandibles or "hard jaws."— Com- 
pare in every respect with the maxillae. In 
which direction do the mandibles open? To 
what are they connected ? Draw. 

Push the outer mouth parts aside and find 

(g) The tongue. — Study its position, shape, size, 
structure, etc. Does it bear appendages? 

Does the head show indications of being composed of 
segments ? If so, of how many ? In the locust is cepb- 
alization carried to a greater or less extent than in the 
lobster? Why? Judging from the number of pairs of 
appendages or traces of such, of how many segments 
does the head consist? 

Make enlarged drawings of the head as seen from the 
front and from the side, showing in each case all of the 
structure visible. 

c. The thorax. — What proportion of the body does it 
form? Of how many distinct pieces is it com- 
posed? What appendages does it bear? How 
are they situated % 



LOCUST 177 

Make out the following parts : 
The first segment forming 

1. The prothorax. — What is its shape as seen 

from above? From the side? How is it con- 
nected to the parts preceding and following it ? 
How does it compare in size with the other seg- 
ments of the thorax? Does it bear append- 
ages ? Notice the expansion, the pronotum, 
of its tergal portion. Try to make out the fol- 
lowing plates composing the prothorax : on the 
dorsal side, beginning at the anterior end, the 
praescutum, the scutum, the scutellum, and 
the postscutellum; on the ventral side, parts 
corresponding to the sternum of the lobster, a 
soft, flexible membrane with a posterior hard- 
ened piece. Note the hairy tubercle, also at the 
side in the membranes connecting the protho- 
rax and the mesothorax, the opening or spira- 
cle. Examine the legs. Number? Color? 
Position ? To what parts are they attached ? 
In what direction do the joints bend ? Exam- 
ine a leg carefully and make out the following 
parts : coxa, trochanter, femur, tibia, and 
tarsus or foot. Study carefully the structure 
of each part. Draw one of the legs. 

Draw the prothorax, showing dorsal, ventral, 
and side views. 

Examine the second joint or 

2. The mesothorax.— Shape? Connections? What 

appendages does it bear? How are they situ- 
ated ? Does this segment bear any spiracles ? 
Compare in all respects with the prothorax. 
Find the two side plates, the episternum in 
front and the epimeron behind, comprising 

12 



178 THE BIOLOGY OF THE ANIMAL 

this segment. What is the shape of the scutum ? 
Of the scutellum ? Of the sternum ? Note the 
wings or "wing covers." Where and how 
are they attached ? What is their structure ? 
Color ? Shape ? Size ? Compare the legs with 
those on the prothorax. 

Draw the mesothorax, showing all the parts. 

3. The metathorax. — Compare this segment in 
shape, size, structure, etc., with the preceding 
segments. Compare also the appendages, both 
the legs and the wings, with the similar ap- 
pendages on the other parts of the thorax, 
noting especially the shape, size, texture, fold- 
ing, venation, color of the wings, and the shape 
and arrangement of the joints of the legs. Are 
there any spiracles on this segment? If so, 
where ? 

Draw the metathorax, also the appendages. 

d. The abdomen. — How is this connected to the thorax ? 
Shape ? Size as compared with the head and the 
thorax? What is its structure? Count the see:- 
ments on the dorsal and on the ventral side. How 
does the number on the upper side compare with 
that on the lower? Does this region bear any 
appendages? Examine the first segment of the 
abdomen. Does it have both tergum and ster- 
num? Note the large opening, the "ear," with 
the membrane or "drum" stretched across it. 
How many " ears " are there ? Does this segment 
bear a spiracle ? If so, what is its position ? Note 
on each side of the abdomen a longitudinal fold. 
Pull the tergal and sternal regions slightly apart. 
Is this fold composed of a flexible membrane? 



LOCUST 179 

Examine the spiracles or stigmata. How many 
do you find on each segment? What is their 
position? Shape? Note the variations in the 
last few segments of the body in the two sexes. 
The females can be distinguished as having the 
abdomen terminate in four curved prongs. Ex- 
amine such a specimen. How does the number 
of sterna differ from the number of terga? In 
the female the last sternum forms the subgeni- 
tal plate. Compare it in shape and size with 
the other sterna. At the posterior end of the 
subgenital plate is the egg-guide. What is its 
structure ? Study the structure of the ovipos- 
itor, which consists of the two pairs of curved 
appendages already mentioned, together with a 
third pair lying between the first two. Notice 
the shape, size, and structure of each pair, their 
direction of motion, etc. To which segment is 
each pair attached ? Find lying above the base 
of the uppermost pair a tergum for which there 
is no corresponding sternum. At the base of 
each of these curved appendages is a small plate, 
the podical plate. Find the opening, the anus, 
between them. What relation does this bear to 
the opening of the oviduct ? Just below the pod- 
ical plates are two other organs, the cerci. To 
which segment are they attached? Compare 
these with the parts of the ovipositor. Compare 
the abdomen of a male with that of the female. 
How many segments in the entire body ? 
Draw the abdomen of each as seen from the side and 
from above. 

Internal Anatomy. — Use, if possible, recently killed 



180 THE BIOLOGY OF THE ANIMAL 

specimens. In studying the internal structure of the 
locust, the two specimens are to be used in the follow- 
ing manner: With the first one, cut off the wings, cut 
the body in two lengthwise with a very sharp scalpel, 
then, insect in hand, study the features mentioned here- 
after. After having done this, prepare the second speci- 
men as follows: Remove the wings, fasten the insect, 
ventral side downward, in the dissecting-dish containing 
fifty per cent, alcohol, by putting pins through the last 
abdominal segment and each of the hind-legs, turning 
the latter outward. Then begin at the posterior end, 
and with fine, sharp scissors cut the skin along each side 
of the body above the spiracles, turning the skin forward 
as it is loosened, thus unroofing the body. Be espe- 
cially careful not to injure the heart, which lies just be- 
low the skin. Then proceed to verify the facts learned 
from the first specimen. 

a. The integument. — Of how many layers is it com- 
posed ? Can you find both epidermis and cuti- 
cle ? What differences in their thickness, text- 
ure, flexibility, color, and arrangement on the 
bod}r? Does the integument bear any outgrowths 
corresponding to the " hairs " found on the lob- 
ster ? If so, do they correspond in general posi- 
tion to those on the latter animal? Put a piece 
of the integument into dilute hydrochloric acid. 
Do you get the same results as you did with the 
lobster's shell ? Does the integument of the in- 
sect contain carbonate of lime ? 

h. The heart (lying just under the skin). — Position? 
What is its relation to the ridge running down 
the middle of the back? Shape? Structure? 



LOCUST 181 

Color ? How far does it extend ? Does it give 
off branches ? 

c. The abdominal muscles. — Some can be seen only 

after the removal of the digestive and reproduc- 
tive organs. Position ? Arrangement ? In what 
direction do their fibres run? Color? Attach- 
ments ? Put a small piece of muscle tissue into 
a drop of normal salt solution and examine under 
the high power. What is the microscopic struct- 
ure of the insect's muscle ? 

d. The wing muscles. — Position ? Arrangement ? 

Number? Direction of fibres? To what are they 
attached at each end ? How are those on oppo- 
site sides of the body separated from each other? 
Is there any such separation between the wing 
muscles and the abdominal muscles ? 

Lying beneath the abdominal muscles find 

e. The corpus adiposum. — What part of the body 

does it occupy ? Structure ? Color ? Examine 
some of it under a low power. 

f. The tracheae. — If a recently killed specimen be 

placed in water the trachese will appear as delicate, 
glistening white tubes. What is their relation to 
the spiracles ? Position ? Shape ? Make out if pos- 
sible six longitudinal trachea?: two spiracular, two 
dorsal, two ventral. Examine some of them under 
a low power and note their structure. Are they 
open or closed ? If open, what keeps them so ? 

With the fine forceps pick away all of the mus- 
cles in the thorax and abdomen and find 

g. The Digestive System. 

It consists of the following parts in order, pro- 
ceeding from before backward : 



182 THE BIOLOGY OF THE ANIMAL 

1. The oesophagus. — What is its position? In 

which direction does it extend ? What is its 
shape? Color? Notice the opening, the occip- 
ital foramen, by means of which the cavity 
of the head communicates with that of the 
thorax. Note also the large muscles running 
from the inner ends of the jaws up into the 
head. To what are they attached ? 

2. The crop. — In what part of the body does it lie? 

"What is its relation to the oesophagus? Shape ? 
Color ? Structure ? Examine its contents with 
the microscope. What does it contain ? Look 
for small salivary glands among the muscles 
under the crop, and, if possible, trace the duct 
which places the glands in communication with 
the mouth. 

Hidden by the anterior ends of the gastric 
coeca find 

3. The proventriculus or "gizzard." — Eelation 

to the crop ? In what segments does it lie ? 
Shape? Structure? Color? 

4. The ventriculus or stomach. — Position ? 

Shape? How is it connected to the proven- 
triculus ? Structure ? Color ? 

5. The gastric coeca. — What is their relation to 

the proventriculus and the ventriculus ? How 
many are there ? What is their shape ? Struct- 
ure ? Color ? With what do they connect ? 

6. The ilium. — Eelation to the ventriculus ? How 

long is it ? What is its shape ? Color ? Struct- 
ure ? In what direction does it run ? Do you 
find in it anything resembling a valve ? 

At the junction of the stomach and ilium 
look for 



LOCUST 183 

7. The Malpighian or urinary tubules. — To 

what are they connected ? Are thej 7 few or 
many in number? What is their shape % Color ? 
How far into the anterior end of the body do 
they extend ? 

The continuation of the ilium forms 

8. The colon.— Position? Shape? Size? Color? 

Structure ? 

9. The rectum. — Compare in all respects with the 

colon. Look for the rectal glands surround- 
ing the upper end of this portion of the ali- 
mentary canal. 
Make a drawing showing a vertical longitudinal sec- 
tion of the digestive system. 

Examine female specimens for the ovaries and ovi- 
ducts. 

h. The ovary. — Position? Shape? Size? Color? Look 
for eggs. How many are found ? What part of 
the body do they occupy? What is their shape? 
Size ? Color ? Examine under the low power. 

i. The oviducts. — How many? What is their rela- 
tion to the ovary ? To the posterior portion of 
the alimentary canal? Where do they open to 
the exterior? 

In male specimens endeavor to find 

j. The testes and the vasa deferentia. — The former 
lie on the intestine in the third, fourth, and fifth 
abdominal segments. Compare these parts with 
the reproductive organs of the female. 

k. The air-sacs. — What is their relation to the trachea?? 
Look for two very large sacs in the pro thorax. 
What is their position? Shape? Size? How 



184 THE BIOLOGY OF THE ANIMAL 

many in the rest of the thorax? How many in 
the abdomen ? Compare them with those in the 
thorax. 

Remove all of the muscles and digestive organs 
from the thorax and abdomen. 

I. The Nervous System. 

The principal parts of this system are the fol- 
lowing : 

Lying on top of the oesophagus, between the 
compound eyes, find 

1. The supra-cesophageal ganglion or "brain." 

— What is its shape ? Size ? Color ? Compare 
with the " brain " of the lobster. 

Running from the " brain " to the eyes are 

2. The optic nerves. — What is their shape ? 

Length ? 
Lying below the oesophagus look for 

3. The infra-oesophageal ganglion. — How con- 

nected to the supra - oesophageal ganglion ? 
What is its shape ? Size ? 
On the side of the crop are 

4. The gastric ganglia. —What is their shape? 

Size as compared with the supra- oesophageal 
ganglion ? 

Lying on the floor of the thorax are 

5. The thoracic ganglia. — How many are there ? 

How are they connected ? What is their shape ? 
How do they compare with the " brain " in size ? 
Lying on the floor of the abdomen are 

6. The abdominal ganglia. — How many are 

there ? How does their number compare with 
that of the abdominal segments ? How are 
they connected? In w T hat segments do they 









LOCUST 1 85 

lie % How do they compare in shape and size 
with the thoracic ganglia ? 

How does the nervous system of the locust 

compare in structure with that of the lobster % 

What resemblances and differences do you find ? 

Make a diagram of the nervous system as seen from 

above. 

m. The thigh muscles. — With a pair of fine scissors or 
a sharp scalpel cut the integument along the pos- 
terior edge of the femur of one of the third pair 
of legs, carefully turn back the outer flap thus 
formed, and notice the arrangement of the mus- 
cles within this segment. Judging from the di- 
rection of the groups of fibres, how many distinct 
muscles does this segment contain ? Are any of 
the groups arranged to correspond with the pe- 
culiar tile -like pattern seen on the outer surface 
of this segment ? 

PHYSIOLOGY 

Many of the following questions may be answered as 
well from a study of dead as from living specimens. 

a. The oody as a whole. — Is its shape at all related to 
the animal's mode of life ? What advantages 
arise from having the body made of segments? 
What reasons can you give for the grouping of 
the segments into regions % Why are the append- 
ages jointed ? What appears to be the principal 
function of each region, as determined from its 
structure and appendages ? Has the insect any 
skeleton ? If so, how does it compare structurally 



186 THE BIOLOGY OF THE ANIMAL 

with that of the lobster ? How is the body pro- 
tected? What modes of locomotion has the ani- 
mal ? What reasons can you give for the various 
colors found on the body ? Do you find any para- 
sites — e. g., mites — on the outside of the body, or 
worms within ? What means of protection from 
its enemies has the iocust ? 

o. The head. — What range of motion has the head ? Is 
it segmented ? Why ? Give reasons for its mode 
of connection to the thorax. Why are there both 
simple and compound eyes ? Why are they situ- 
ated as you find them ? In what directions can 
the locust look ? Can the insect wink ? How 
does it close its eyes ? What is the probable use 
of the antennae ? Why are they jointed ? What 
reasons can you give for their position ? How do 
you account for the structure of the labrum ? Of 
the labium ? Put a living locust under a tumbler, 
and feed the insect with a few blades of fresh 
grass. In what direction do the jaws move? 
Why? What is the use of each kind of jaw? 
When standing on a flat surface, can the locust 
reach down to that surface with its mouth? 
What is probably the use of the palpi? Do 
they assist in feeding ? Watch closely to see if 
they do not pick up the food (grass), and hold it 
while pieces are being bitten off. Are there any 
nostrils ? 

c. The thorax. — What is the function of the prothorax ? 
Of the tubercle ? What reasons can you give for 
the structure of the dorsal portions of the meso- 
thorax and metathorax ? Of the ventral portions ? 



LOCUST 187 

What uses have the first pair of wings, or the 
" wing covers " ? The wings ? How does their 
structure fit them for their use ? For what pur- 
pose are the veins in the wings ? How are the 
wings folded ? Unfolded ? What is the use of 
the first pair of legs ? Second pair ? Third pair ? 
Of the spines on the tibia of the third pair ? Of 
the projections of the femur at the side of the 
joint between the femur and tibia? Of the hooks 
and pads ? What is the position of the w T ings 
and legs when the insect is at rest ? When pre- 
paring to leap? When flying ? When feeding 
on a blade of grass ? Why do the joints of the 
various legs bend in so many different directions ? 
Compare with the lobster. Why are the wing- 
muscles so large ? 

d. The abdomen. — Why is it segmented ? Of what mo- 
tions is it capable ? Why is there a membrane 
between adjacent segments? Hold a living lo- 
cust in the fingers and study its mode of breath- 
ing. Give reasons for the structure of a single 
segment. What is the use of the spiracles ? 
Why are there so many? Can a locust be 
drowned by holding its head under water ? How 
does the insect "sing"? What is the use of the 
air-sacs ? Why are there no external ears ? Why 
should not the ears be on the head ? How does 
the shape of the ovipositor fit it for its use? 
What reasons can you give for the presence of 
such a complicated digestive system? Do you 
find that it contains much or little food? Exam- 
ine some of the contents under a microscope. Of 
what does the food consist ? 



188 THE BIOLOGY OF THE ANIMAL 

General Questions. — What structural relationships do 
you find existing between the lobster and the locust ? 
Do you find any structural features which these two 
animals possess in common with the earthworm ? What 
do you consider to be the main points in which the last 
differs from the other two ? 

Use any butterfly or moth, or a beetle, bee, or cricket 
for comparison. 



Mollusc Shells 
Example 1. — Fresh- water Mussel (JTnio Sp. or Anodonta Sp.) 

Material. — Mussels may be found in rivers, ponds, 
and lakes throughout the country. If more convenient, 
clams may be used. These may be had from fish-deal- 
ers and restaurants everywhere. The shells may be pre- 
served dry or in alcohol. For their study the stu- 
dent will need nothing but a dish of water, some dilute 
hydrochloric acid, a hand-lens, and a test-tube or tum- 
bler. 

Oyster -shells will be especially interesting for com- 
parison. 

Method of Examination. — Remove the animal from 
its shell, noting carefully the points where the connec- 
tion between the shell and soft parts is closest. If, as 
will be the case with the living animal, the shell should 
be difficult to open, place it in warm but not boiling 
water for a few minutes. Before studying the other 
structural features, put some of the shells, if dry, into 
water to soften the hinge-ligament, and some pieces 
into the dilute hydrochloric acid in a test-tube or tum- 
bler. 

MORPHOLOGY 

a. The entire shell. — What is its shape? Where are the 
points of its greatest length, breadth, and thick- 



190 THE BIOLOGY OF THE ANIMAL 

ness ? Of how many parts or valves does the 
shell consist ? How are the valves held together ? 
Can you distinguish a right and a left side to the 
shell ? Dorsal and ventral sides ? Anterior and 
posterior ends? Do you find that some of the 
shells of the same kind are more convex than 
others? Of what use is the shell? Put a small 
piece into weak hydrochloric acid. What is the 
result? Compare with the "shell" of the lob- 
ster and the integument of the insect. How is 
the mussel shell probably formed ? 

Notice that a portion of the shell is usually 
covered with a deposit of mud. Which portion 
is it? How thick is the deposit? What is the 
direction of the line between the clean and the 
mud-covered portion ? Does the latter portion 
show more or fewer signs of wear, such as ab- 
sence of "epidermis," fading of colors, smooth- 
ness of surface, etc., than the other ? 

b. The single valve. 

On the outside study 

1. The shape. — What is the shape of its outline? 

Are the two ends shaped alike ? The margins ? 
Where is the valve thickest ? Where thinnest? 

2. The epiostracum or "epidermis." — Does it 

cover the entire valve ? What is its color ? 
Are there any variations in color ? Where is 
this covering thickest? Can the epiostracum 
be removed from the shell ? What is its use ? 

3. The hinge - ligament. — What is its position? 

What reason can you give for this? What is 
its shape ? Of what is it made ? Soak it in 
water, if the shell be dry, until the ligament 



FRESH- WATER MUSSEL 191 

becomes flexible. What is its use ? Why are the 
shells of dead mussels and clams always open ? 

4. The lines of growth. — What is their position? 

Shape ? Number % Where do they begin ? Is 
their number the same for the two valves of 
the same shell? Are they everywhere at a 
uniform distance apart ? 

5. The umbo or "beak." — What is its position? 

How is it formed ? How does it compare in 
age with the rest of the shell ? Does it differ 
in color from the other regions ? If so, explain. 
On the inside find 

6. The hinge-teeth (not present in Anodontd). — 

What is their position? Shape? Structure? 
Number on each valve ? Note the two kinds — 
the one pointed, the cardinal teeth ; the other 
elongated, the lateral teeth. How many of 
each kind are there on each valve ? What is 
their use ? 

7. The lining of the valve. — What is its color? 

How does it differ from the outside of the 
valve ? Are there any variations in color ? If 
so, to what are these due ? 

8. The pallial impression. — What is its position? 

How distinguished? What is its relation to 
the impressions of the adductor muscles ? 

9. The impressions of the adductor muscles. — 

How are they distinguished ? What is the posi- 
tion of each ? Color, shape, and size of each ? 
Note also the paths of shifting of these muscles. 
In front of the posterior adductor impression 
find 
10. The scar of the posterior retractor muscle. 
— Compare with preceding. 



192 THE BIOLOGY OF THE ANIMAL 

Find also opposite the upper end of the im- 
pression of the anterior adductor muscle 

11. The scar of the anterior retractor muscle. — 

Compare with the preceding. 

Opposite the lower end of the impression of 
the anterior adductor muscle find 

12. The scar of the protractor pedis muscle. — 

Compare with the above. 

Break a valve in two, examine the broken edge with 
a hand-lens, and note the structure of the valve. 

Make a drawing of the outside and inside of each 
valve, and of a transverse section through the thickest 
part of one of the valves. 

Example 2.— Pond Snail {Lymnmus Sp.) 

Material. — This snail is abundant in ponds and slow- 
flowing streams. Its large size makes it especially favor- 
able for the stud}' of the univalve shell. For compara- 
tive study use the shells of any land or water snails that 
may be had. A penknife or dull scalpel and a hand- 
lens will be needed. 

Method of Examination. — Before removing the body 
from the shell (which may be done by dropping the snail 
into hot water for a few minutes, then picking out the 
body with a pin or needle), closely observe the manner 
in which and the places where the body is connected to 
the shell. Notice also how far back in the shell the 
body lies when completely contracted. 

With the penknife prepare longitudinal and cross sec- 
tions of the shell to show the structure of the colu- 
mella. When applicable use the questions given for 
Unio or Anodonta ; also notice 



POND SNAIL 193 

a. The whorls or turns of the spiral. — How many are 
there ? What is their arrangement ? What vari- 
ations in shape, size, and color clo you find? Trace 
the suture or line of junction between two 
whorls. 

h. The body -whorl or first turn of the spiral. — What 
is its position? Shape? Size as compared with 
others? How much of the entire shell does it 
form ? 

c. The spire. — What is its structure? What is the 

number of whorls composing it? What is the di- 
rection of the spiral? 

d. The apex. — What is its structure ? Compare in age 

with other parts of the same shell, also compare 
with the umbo of TJnio or Anodonta. 
Cut a shell in two lengthwise and notice 

e. The columella or axis around which the whorls 

turn. — How is it formed ? Does it extend 
throughout the length of the shell? Is it solid 
or hollow? 

/. The mouth. — What is its shape ? Is it the largest 
part of the cavity of the shell ? Notice the in- 
ternal lip or side towards the columella, and the 
external lip or side away from the columella. 

g. The peristome or rim of the mouth. — What is its 
shape ? Size ? Does it bear any outgrowths, as 
teeth, etc. ? 

h. The muscular impression. — Where is it? What 
is its shape ? Color ? How is it formed ? 
Draw the shell as seen from the front, also a longitu- 
dinal section. 



The Soft Parts of tlie Fresh-water Mussel 

Method of Examination. — If the animal be living, open 
the shell as directed under the head of "Mollusc Shells." 
Remove the right valve by cutting through the adductor 
muscles at their points of attachment to the valve. Ex- 
amine the specimen in a dissecting-pan containing fifty 
per cent, alcohol, which should be removed as often as 
it becomes turbid. If freshly killed specimens be used, 
the alcohol will coagulate the slimy excretion on the 
surface of the body. This may be cleaned off with a 
camel's-hair brush. 

External Anatomy, 
a. The relation between the body and the shell. — 
Does the body fill the shell? Is it in contact 
with the shell at all points ? What holds it in 
place? Does it have the same shape as the shell? 
How do you distinguish the anterior end of the 
body? 

o. The pallium or mantle. — Why is it so called? What 
is its shape? How many lobes or folds has it ? Are 
they connected ? If so, where ? Do they corre- 
spond in size and shape with the valves of the 
shell? Where is the mantle attached to the shell? 
Where to the body ? What is its texture ? Color ? 
Do you find any variations in either ? To what 
are such variations due? Notice a thickened 
band, the pallial muscle, near the margin. 



FRESH-WATER MUSSEL 195 

What is the texture of the extreme margin of the 
mantle ? Color ? Structure ? Notice on the dor- 
sal surface, in front of the posterior adductor 
muscle, a thin portion of the mantle. This por- 
tion covers the pericardial chamber. 
a. The adductor muscles of the valves. — How many 
are there ? How are they situated ? How are 
they distinguished from the rest of the body? 
What is the shape and size of each? Do they 
differ in shape and size ? How are they attached 
to the shell ? Are they covered by the mantle ? 
How do you account for their number ? In what 
direction do their fibres run ? Why do they run 
in this direction ? Why are these muscles called 
" adductors " ? What advantage in having them 
in the position in which you find them ? 

At the upper end of each adductor muscle look 
for 

d. The retractor pedis muscles. — Compare with c in 

every respect. Do these muscles form a " scar " 
on the shell ? 
A little below the anterior retractor muscle find 

e. The protractor pedis muscle. — What is its shape? 

Size ? Compare with the adductor and retractor 
pedis muscles in every respect. 

At the posterior end of the body find 

/. The siphons. — How many are there? How are 
they formed ? What is their relative position to 
each other ? How are they separated ? How 
long are they ? How wide ? With a pipette in- 
ject water into each siphonal opening. Where does 
the cavity of each lead? Note the tentacles — 
their number, shape, size, color, and structure. 



196 THE BIOLOGY OF THE ANIMAL 

Turn back one of the lobes of the mantle and 
note 
g. The pallial cavity. — How is it formed ? "What does 
it contain ? Note its division into a large ventral 
cavity, the branchial cavity, and a much small- 
er dorsal cavity, the hinder portion forming the 
cloacal cavity. 

A. The abdomen. — What is its relation to the muscles? 
What is its shape ? Color ? Is it bilaterally sym- 
metrical ? Is there a head ? Are there any bones 
in the body ? How is it held in the shell ? 

Projecting from the lower margin of the ab- 
domen is 

i. The foot. — What is its position with regard to the 
abdomen? To the pallial lobes? To the gills? 
What is its shape? Size as compared with the 
abdomen ? Color ? Structure ? To what is it 
attached ? In what direction does it project ? 

j. The gills or gill-plates. — What is their position 
with regard to abdomen, foot, siphons, and man- 
tle ? Number ? Shape ? Size as compared with 
the mantle folds ? Color ? How attached to the 
body proper and the other parts ? Cut along the 
line of attachment of the outer gill to the mantle. 
Notice that a canal, the supra - branchial or 
cloacal chamber, is thus laid open. Notice also 
running down into the gill between its two faces 
a number of fine tubes, the water-tubes, sep- 
arated from one another by partitions. These 
tubes are closed at the lower margin of the gill, 
as may be proved by passing a fine bristle into 
a tube. Carefully split open a gill, and examine 
both surfaces with a hand-lens. Note that each 



FRESH-WATER MUSSEL 197 

gill consists of two lamellse united by the par- 
titions mentioned above, which are the inter- 
lamellar junctions. Examine also with the low 
power, and try to make out the oval inhalent 
apertures opening on the face of the gill into 
the water-tubes. Scrape the surface of a gill of 
a living mussel, and examine the ciliated cells 
thus set free. Examine a piece of a split gill of 
a living mussel under the low power, and note the 
ciliary action. Compare the gills with each 
other as regards shape, size, color, structure, at- 
tachment, etc. 
Make drawings showing the gross and the minute 
structure of a gill. 

Jc. The mouth. — What is its position with regard to 
foot, anterior adductor muscle, siphons, and gills ? 
What is its shape ? Size ? Are there any jaws ? 
Teeth ? A tongue ? What kind of food can the 
mussel eat 2 

I. The labial palpi. — What is their position with re- 
gard to the mouth and gills ? Number ? Shape ? 
Color? Attachments? Compare with gills as 
regards shape, size, and structure. Are they at 
all like the palpi seen on the lobster and locust ? 

m. The anus. — What is its position? With which si- 
phon is it connected ? 
Make the following drawings : (1) A side view of the 
mussel lying in one valve of the shell, to show the posi- 
tion of the muscles, etc. ; (2) a side view with one man- 
tle lobe turned back ; (3) a side view with mantle lobe 
and gills turned back. 



198 THE BIOLOGY OF THE ANIMAL 

Internal Anatomy. 
A. — The Digestive System. 

Using an alcoholic specimen, push a guarded 
bristle into the mouth, and with scissors cat open 
the alimentary canal from the mouth to the 
stomach, using the bristle as a guide. Then in a 
similar manner trace the course of the intestine 
backwards from the anus. If necessary, the ali- 
mentary canal may be injected through the anus 
with a mixture of equal parts of plaster of Paris 
and water. The mixture must be strained through 
SlYig cloth before being used. 

a. The month. — This has already been studied. 

h. The oesophagus — What is its relation to the 
mouth as regards diameter and the direction in 
which it runs ? To the anterior adductor muscle ? 
What is the nature of its walls ? 

c. The stomach. — How is it distinguished from the 

oesophagus ? What is its position with regard to 
the hinge-ligament ? 

Find surrounding the stomach and oesophagus 
a dark-colored mass, 

d. The liver, — What is its relation to the anterior 

adductor muscle ? Look for the opening of the 
bile-duct into the oesophagus anterior to the 
opening of the latter into the stomach, and into 
the stomach itself. 

e. The intestine. — Into what part of the stomach 

does it open? Trace it through the yellowish- 
white generative gland, by picking away the 
latter with the fine forceps. Does it enter the sub- 
stance of the foot? What is its course through 



FRESH-WATER MUSSEL 199 

the abdomen of the animal ? What is the rela- 
tion of its posterior end, the rectum, to the 
hinge-ligament ? To the posterior adductor mus- 
cle? Notice that the rectum runs through the 
pericardial cavity. Into what does the anus open ? 
Notice the prominent ridge or typhlosole on the 
ventral side of the rectum. Where is this ridge 
largest ? How does this compare in position and 
structure with the typhlosole of the earthworm? 
Draw a diagrammatic longitudinal section of the 
body, showing the course of the digestive system. 

B. — The Circulatory System. 

Eemove from the shell a living mussel in water, 
being very careful not to injure the soft parts, 
and note the beating of the heart as seen through 
the pericardial wall. Study the number of beats 
per minute and the movements of the heart. 
Open the pericardium, noting the thickness of 
its wall and the shape and extent of the pericar- 
dial 'cavity. If living specimens cannot be had, the 
heart may be found by cutting the upper edge of 
the upper siphon forward to the umbo. Notice 
the heart, consisting of a median ventricle and 
two lateral fan-shaped auricles. 

a. The ventricle (wrapped around the intestine). — 

What is its position in the pericardium ? What 
is its shape ? Size ? Color ? Are its walls firm 
or flexible ? Trace from the ventricle an ante- 
rior aorta on the upper side, and a posterior 
aorta on the lower side of the intestine. 

b. The auricles. — What is their relation to the ven- 

tricle? What is the structure of their walls? 



200 THE BIOLOGY OF THE ANIMAL 

How do they communicate with the ventricle? 
What is the shape of their cavity ? What is their 
relation to the gills? Look for veins running 
along the upper edges of the gills and communi- 
cating with the auricles. 

C. — The Nervous System. 

Using an alcoholic specimen, and dissecting in 
a clish of fifty per cent, alcohol, endeavor to make 
out the following parts : 

a. The cerebral ganglia. — Separate the palpi on 

each side of the mouth, and just under the skin, 
between their bases, the ganglia will be found. 
What is the position of the ganglia with regard 
to the mouth ? How many are there ? What is 
their shape? Size? Color? In what direction 
do nerves pass off ? Look for nerves passing to 
the anterior adductor muscle ; to the palpi ; to 
the mantle lobes ; to the foot, connecting with 
the pedal ganglia, and hence called cerebro- 
pedal connectives ; to the parieto-splanchnic 
ganglia at the posterior end of the body, and 
forming the cerebro-splanchnic connectives, 
and from one cerebral ganglion across over the 
mouth to the other ganglion, the inter- cerebral 
commissure. Do you find that these ganglia 
are bilaterally symmetrical as regards position 
and branches? 

b. The parieto-splanchnic or visceral ganglia. — 

To see these, separate the gills at the posterior 
end of the body. Compare these ganglia with 
the cerebral ganglia in all points of structure. 
Endeavor to make out nerves running to the 



FRESH- WATER MUSSEL 201 

posterior adductor muscle, to the gills, and to the 
pallial lobes and connectives, already partially 
traced, running to the cerebral ganglia. 

c. The pedal ganglia — Very careful dissection will 
be needed to show these. They lie in the middle 
line of the foot, close to the point where the foot 
and the abdomen join, and about one-third of the 
length of the former organ from its anterior end. 
Compare these ganglia with the others studied, 
and try to trace the connectives running to the 
cerebral ganglia. Look for the pair of otocysts, 
or " ear," a short distance behind and below the 
pedal ganglia. 

Make a diagram showing the position of all of the 
[■ano-lia and the course of the nerves. 



L o 



D. — The Excretory System. 

Lying under the pericardium, extending for- 
ward from the posterior adductor muscle, find on 
each side a wide, dark-colored tube with spongy 
walls. Endeavor to make out the lower portion 
of the tube with its folded spongy walls, the 
" kidney," or organ of Bojanus, and a thin- 
walled conducting tube, the " ureter." Look 
for the opening of the latter into the anterior 
end of the pericardium. Pass a bristle from 
the pericardium into the organ of Bojanus. 
Opening into the cloacal chamber immediately 
below and behind the anterior end of the peri- 
cardium look for a small pore, the renal ap- 
erture or external orifice of the "kidney." 
Near the renal aperture look for the genital 
aperture. 



202 THE BIOLOGY OF THE ANIMAL 

E. — The Examination of Transverse Sections. 

"Wedge open the valves of living specimens and 
put them into one per cent, chromic acid for about 
two days, then transfer to seventy per cent, and 
ninety per cent, alcohol for one day each. Re- 
move the body from the shell, being careful to 
disturb the parts as little as possible. Place the 
mussel on a board, and with a razor cut the en- 
tire body into a series of parallel transverse sec- 
tions, about a quarter of an inch thick. Float 
these sections in order in a long dissecting-pan 
containing fifty per cent, alcohol, and study the 
relation of the various organs. 
Draw the following sections : (1) Through the stom- 
ach, (2) through the heart, (3) through the middle of 
the posterior adductor muscle. 

As regards structure, which of the animals that you 
have studied does the mussel most closely resemble ? 

Habits. 

A number of interesting observations on the habits 
of the fresh- water mussel may easily be made by placing 
specimens in an aquarium or in tubs or pans having the 
bottom covered with three or four inches of sand or 
mud. By changing the water from time to time the 
animals may be kept alive for weeks. Study the posi- 
tion of the animal in the water, the manner in which the 
foot is used as an organ of locomotion, watch the water 
flowing into and out of the siphons by scattering parti- 
cles of indigo near the orifices, test the sensibility of the 
siphonal tentacles by gently touching them with a bris- 
tle, etc. 

For comparative work use the clam (Mya or Venus) or 
the oyster (Ostrea). 



Frog (Rana Sp.) 

Material. — Almost any creek, pond, or marsh will fur- 
nish an abundance of frogs during the warm season, but 
especially in the spring. They should be caught unin- 
jured. Maimed and mutilated specimens are of little 
value for anatomical purposes, to say nothing of the 
cruelty practised in capturing them with sticks, stones, 
and spears. City students may be supplied by fish-deal- 
ers, some of whom are usually acquainted with the men 
who supply the markets with frogs' legs. The frogs 
may be kept in a deep box covered with wire netting, 
and containing several sods, which should frequently be 
watered to keep the grass in good condition. At one 
end of the box may be placed a pan — a dripping-pan 
will answer — filled with water, in which the frogs may 
swim. The box should stand in a dimly lighted, cool 
place, as in a cellar, and the water should be changed 
every few days. 

If the frogs vary much in size, the large ones should 
be kept separate from the smaller ; otherwise the latter 
will be eaten. In a properly prepared box specimens 
may be kept all winter, with no other care than chang- 
ing the water in the pan and moistening the sods. It is 
almost, if not quite, impossible to get the creatures to eat 
anything besides their smaller companions, no matter 
how tempting may be their food. Should some of them 
be frozen in the pan, let them thaw slowly, and they 
will be in as good condition as ever. 



204 THE BIOLOGY OF THE ANIMAL 

Both living and alcoholic material should be used. 
The latter will dissect more easily than the freshly 
killed specimens. Frogs may be killed in a few minutes 
by being placed in a covered bowl with a wad of cotton 
or a piece of cloth, upon either of which a few drops of 
ether or chloroform have been poured. To joreserve 
them, open the body by cutting along the median ven- 
tral line from the fore to the hind limbs. Open the 
skull and the spinal canal by cutting away the bone 
with scissors. Place the body in seventy per cent, alco- 
hol for two or three days (being careful to see that the 
abdominal cavity is kept open, so that the alcohol may 
have access to the internal organs), then transfer for a 
day or two to stronger alcohol. 

Two skeletons should be prepared, one having the 
bones separated, the other having them connected by 
the natural ligaments. The first one may be prepared 
by cutting off the bones as much as possible of the flesh 
of a fresh or alcoholic specimen, and soaking it for sev- 
eral days in water or in water to which has been added 
just enough potash to give the solution a decidedly slip- 
pery feel. Warmth will hasten the process. When suffi- 
ciently macerated, the flesh may be removed from the 
bones with a tooth-brush. If it be desirable to keep the 
bones of the fore and hind feet separate, wrap each of 
those organs in a piece of fine cloth. After being cleaned 
the bones may be bleached by laying them in a sunny 
window where they will not be blown away. The sec- 
ond skeleton should be made from a freshly killed frog, 
though an alcoholic specimen will do. Cut off the flesh, 
beiug very careful not to trim the ligaments too closely 
at the joints, nor to cut away the cartilaginous portion 
of the skeleton, especially that of the hyoid apparatus. 
Throw the preparation into Wickersheimer's fluid for a 



FROG 205 

week or two, then cut away all of the superfluous ends 
of muscles, ligaments, etc., leaving just enough to hold 
the bones together. In this preparation the mem- 
branous parts will be found to be so flexible as to per- 
mit of all the natural motions of the joints. Specimens 
prepared in this way may be exposed to the air for sev- 
eral years without deterioration. Should the ligaments 
become stiffened, a few days' soaking in the fluid will 
soften them again. 

The instruments and reagents to be provided include 
a medium -size and a small scalpel, scissors, medium- 
size and fine forceps, lens, pipette, bristles, blow-pipe, 
fifty per cent, alcohol, seventy-five per cent, alcohol, 
watch-glass, dissecting - pan, dilute nitric or hydro- 
chloric acid, magenta, normal salt solution, one-half per 
cent, solution of silver nitrate, distilled water, hema- 
toxylin, glycerine, chloroform, eosin, iodine, and micro- 
scope. 

Method of Examination. — Study alcoholic specimens 
in dissecting-pans containing fifty per cent, alcohol. Re- 
cently killed frogs may also be examined advantageously 
in alcohol. While working out the gross anatomy and 
physiology, let the student have in front of him a jar of 
water containing a living frog. 

MORPHOLOGY 

External Anatomy. 

a. Shape. — What is the shape of the body as a whole ? 
Does it possess well-marked dorsal and ventral 
surfaces? If so, how are they distinguished? 
What differences between the shape of the an- 
terior and posterior ends ? Examine several 



206 THE BIOLOGY OF THE ANIMAL 

frogs to find decided variations in shape. Is the 
shape of the body adapted to the frog's mode of 
life? 

h. Size. — What is the length of your specimen ? Width ? 
Where is the place of greatest width ? Of least 2 
Where that of greatest depth ? Least ? 

c. Color. — What is the general color of the body ? Do 

you find decided differences between the colors of 
the dorsal and ventral surfaces ? What colors do 
you find on the dorsal surface? How are they 
arranged? Is the disposition of colors on the 
right the same as that on the left side ? Examine 
a number of frogs and see whether or not they 
are colored alike. Do all show the same arrange- 
ment and the same shades of color? Can you 
give any reasons for the presence and distribution 
of the colors found ? If practicable, examine the 
same frog at different seasons of the year to see 
whether or not there be any variation in the color 
of a single individual. 

d. General Structure. — Note that the entire body con- 

sists of an axial portion, composed of head 
and trunk ; and an appendicular portion, the 
limbs. Study the skin covering the body. What 
is its texture ? Is it closely fastened to the un- 
derlying parts? Does it vary in this respect? 
Does it bear any outgrowths, as scales, hairs, 
feathers, etc. ? 
1. The head. — What is its shape as seen from 
above? From the side? Is it connected to 
the body by a neck ? How do you distinguish 



FROG 207 

the boundary line between head and body ? 
How much of the axial portion of the body 
does the head form? Where is the widest 
part of the head ? What is the shape of its 
anterior end ? Where is the mouth ? What is 
its shape ? In which direction does it open ? 
How far around on the sides of the head does 
the mouth extend ? Compare in position, shape, 
size, mode of opening, etc., with the mouth of 
the lobster. Note the eyes. — What is their 
position? Shape? Color? Are there eye- 
lids ? If so, how many ? How do they differ 
in shape, size, color, texture, mobility, etc. ? 
Compare with the lobster. How do you ac- 
count for the position and prominence of the 
eyes ? Can they in the live frog be depressed 
and raised in the sockets ? If so, give reasons ? 
Look for the brow-spot on a line connecting 
the anterior borders of the eyes. Anterior to 
the eyes find the external nares or nostrils. 
Study their position, size, and shape. What 
is the texture of the skin surrounding them? 
Can they be closed? What reasons can you 
give for the position of the nostrils ? Posterior 
to the eyes find the tympanic membranes. 
What is their shape ? Size? Color? What is 
the texture of the membrane ? How is it sup- 
ported ? Is it tightly or loosely stretched ? 

How many paired openings does the head 
bear ? How many unpaired ? What are they 
in each case ? 
The trunk.— What is its shape ? How does the 
dorsal differ from the ventral surface in shape ? 
Compress the trunk from side to side between 



208 THE BIOLOGY OF THE ANIMAL 

the thumb and fingers. "Where do you feel the 
hard parts of the skeleton ? Note the " hump " 
in the back of a living frog which is sitting 
naturally. JSTote also the ridge, the urostyle, 
running backward from the " hump," and end- 
ing near the posterior end of the trunk. Find 
at the posterior end the cloacal aperture. 
What is its exact position ? Shape ? What is 
its position with regard to the end of the uro- 
style ? 
3. The limbs.— Study first the anterior limbs. To 
what part of the body are they attached ? In 
which direction do they project ? What is their 
shape ? Are they long enough' to reach to the 
tip of the head ? What is their diameter ? Does 
it vary greatly at any point? Make out the 
following regions on each limb : the brachium 
or upper arm, the antebrachium or fore arm, 
and the manus or hand. What portion of the 
entire limb does each of these regions form ? 
In which direction does each point ? Compare 
the brachium and antebrachium with regard to 
length. How many digits or fingers on the 
manus ? Is the pollex or thumb present ? Of 
how many joints does each digit consist ? Do 
you find a web between the adjacent digits ? 
Do they differ at all with regard to the thick- 
ness of the skin covering them ? Do they bear 
nails or claws ? 

Study the hind limb, and make out the fol- 
lowing regions : the femur or thigh, the crus 
or leg, and the pes or foot. Compare as above 
all of the regions with one another and with 
the corresponding regions of the fore limb. 



FKOG 209 

What are the main points of resemblance? 
What are the principal differences? How do 
you explain the latter ? Do you find a hallux 
or great toe ? In what respects does the skin 
of the thigh differ from that on other parts of 
the body ? 
Make diagrams illustrating the main features of the 

external anatomy. 

In what respects, if any, do the appendages of the 

frog resemble those of the lobster and the locust ? 

Internal Anatomy. 
A. The skeleton. 

Study the articulated skeleton prepared in 
Wickersheimer's fluid, using for comparison the 
individual bones of the other skeleton. Note 
the axial skeleton, consisting of the skull 
and vertebral column or " backbone," and the 
appendicular skeleton, composed of the limbs, 
which are more or less closely attached to the 
axis by means of the limb-girdles ; the anterior 
being the pectoral-girdle or shoulder-girdle, 
the posterior the pelvic-girdle or hip-girdle. 

a. The vertebral column. — What is its general ap- 
pearance ? Is it a single bone ? If not, why is it 
called the " backbone " ? Of how many parts 
does it consist ? Is the vertebral column hollow 
or solid ? Notice that the entire column may be 
divided into two regions, an anterior and a poste- 
rior, the latter formed of the urostyle. What 
is the shape of the urost} T le ? Structure ? How 
does its length compare with that of the anterior 
portion of the column ? Is it a single piece, or 
does it consist of segments? To what is its an- 
14 



210 THE BIOLOGY OF THE ANIMAL 

terior end attached ? Posterior end ? Is it solid 
or hollow ? Note the prominent ridge. On what 
part of the urostyle is it found? What is its 
shape ? Near the anterior end and on each side 
find a small hole or foramen, through which 
nerves enter the urostyle. Draw the urostyle as 
seen from the side. 

Examine the anterior portion of the vertebral 
column. Of how many segments or vertebrae 
does it consist ? Are the vertebrae quite alike in 
general appearance ? Examine a single vertebra, 
e.g., the third or fourth, and note that it is a 
bony ring which bears several projections or proc- 
esses. The ventral portion of the ring is the 
centrum or body. What is its shape as seen 
sidewise? What is the shape of its ends? Is it 
composed of dense or of spongy bone ? On the 
dorsal side of the centrum is the neural arch. 
How is it formed ? What is its shape as seen 
from the end? On the dorsal side of the arch 
find a single projection, the spinous process. 
What is its shape ? Length ? In which direction 
does it point ? On each side of the neural arch 
find a transverse process. How do these 
processes compare in shape, size, and structure 
with the spinous process ? In which direction do 
they extend ? Why called " transverse " ? Are 
they attached to any other bones ? Find also a 
pair of anterior articular and a pair of poste- 
rior articular processes. What is the position 
of each pair? Compare in all respects with the 
transverse processes. Why are they called "ar- 
ticular " processes ? Do you find any ribs ? Draw 
the vertebra as seen from the end, from the side, 



FEOG 211 

and from above. Compare all of the other ver- 
tebrae with the one just studied, noting especially 
the first or atlas and the last or sacrum. Does 
the former have a spinous process ? Transverse 
processes ? Anterior articular processes ? Poste- 
rior ? Note the large space left between the roof 
of the neural arch and the base of the skull. 
Look for the projection, the odontoid process, 
on the centrum of the atlas. What is its shape ? 
With what does it connect? Draw the atlas. 
What modification has taken place in the trans- 
verse processes of the sacrum ? To what are they 
attached? Draw the sacrum. Examine two adja- 
cent vertebrae, and note how the articular proc- 
esses of the one move upon the articular proc- 
esses of the other. Examine an entire vertebral 
column, and note the row of openings, the inter- 
vertebral foramina, on each side of the verte- 
bral column, immediately below the articular 
processes. How are these openings formed ? 
Compare these with the foramina found on the 
urostyle. Have you any evidence that the uro- 
style is made of more than one piece ? Is the 
segmental portion of the vertebral column of a 
living or of a recently killed frog very flexible ? 
If so, in which direction does it bend ? 

b. The skull. — What is its shape as seen from above ? 
From below? From the side ? Notice the large 
eye-socket on each side of the cranium. Back 
of each eye-socket find a tubular portion, the 
auditory capsule. What is its position with re- 
lation to the cranium ? To the tympanum ? At 
the anterior end of the cranium find on each side 



212 THE BIOLOGY OF THE ANIMAL 

an olfactory capsule. Examine the lower jaw, 
the mandible or inferior maxilla. What is 

its shape ? What is its position when the mouth 
is closed ? Does it bear teeth ? Are its two sides 
immovably connected ? Of how many parts is 
each half of the mandible composed? On its 
upper edge find a groove in which lies Meckel's 
cartilage. Where does this cartilage begin? 
How far does it extend ? Do j^ou find any fo- 
ramina in the lower jaw ? If so, where are they ? 
Draw the mandible as seen from above. Notice 
that the upper part of the skull consists of a sys- 
tem of parts attached to the cranium and the 
sense capsules. Examine the posterior end of 
the skull and find a large opening, the foramen 
magnum. What is its shape ? Size? What is 
its relation to the neural canal in the spinal col- 
umn ? To the cranial cavity ? Find a convex 
tubercle, the occipital condyle, on each side of 
the foramen magnum. What is the shape of 
the condyle ? What is the direction of its 
longer axis ? The nature of its surface ? Its 
relation to the atlas ? Each condyle is borne 
upon one of the exoccipital bones. What is 
the relation of these bones to the foramen mag- 
num ? What is their shape ? Do the exoccipital 
bones form any part of the auditory capsules? 
Note that each condyle is pierced by a foramen 
which is the exit of the tenth cranial nerve 
(vagus). Notice on each side the ridge along 
which is the junction between the exoccipital 
bone and the pro-otic bone. What is the shape 
of the latter ? What part of the auditory capsule 
does it form? Is any part of the front of the 



FROG 213 

auditory capsule cartilaginous? If so, what is 
the relation of this part to the pro-otic bone? 
Attached to the outer edge of the pro-otic and 
extending downward to the posterior end of the 
upper jaw find the squamosal bone. What is 
its shape ? What is its relation to the tympa- 
num ? Examine the cartilaginous ring, the tym- 
panic ring, upon which the tympanum is 
stretched. What is the relation of the ring to 
the squamosal bones attached to the under sur- 
face of the tympanum ? Find the columella 
auris. What is its structure ? Shape ? To what 
part of the tympanum is it fastened \ Trace the 
columella to its inner end, which closes the open- 
ing or fenestra ovalis in the auditory capsule. 

In carefully prepared skeletons look for a car- 
tilaginous rod, the styloid cartilage, running 
from the pro-otic to the hyoid bone. Examine 
the roof of the skull and find a pair of bones, 
fronto - parietals, extending forward from the 
exoccipitals and pro-otics. What is their shape ? 
How far forward do they extend ? What is their 
relation to the cranial cavity ? Examine the 
sagittal suture, along which these bones are 
united. 

At the anterior end of the fronto - parietals 
look for the sphenethmoid or girdle bone. 
Anterior to the latter is a cartilaginous structure 
on each side of which is a nasal bone. What is 
its shape ? In which direction does it extend ? 
What is its position with regard to the fronto- 
parietal? How is it connected to the latter? 
How does it differ structurally from the sphe- 
nethmoid ? In front of the nasal bones lie the 



214 THE BIOLOGY OF THE ANIMAL 

two pre-maxillae. "What is their shape ? Note 
the ascending process which each bears. What 
is the direction of the process? How are the 
pre-maxillary bones united to each other? To 
the nasal bones ? Extending backward from the 
lower end of each pre-maxilla find the maxil- 
lary bone. How far back can you trace it? 
What is its shape ? What is the shape of the 
lower edge ? Note the teeth. On what part of 
the maxilla are they borne ? How are they ar- 
ranged ? What is their shape ? Do they vary in 
shape and size? How are the maxilla and the 
pre-maxilla of the same side connected ? Do you 
find teeth on the pre-maxilla ? At the posterior 
end of the maxilla find the quadrato-jugal 
bone. To what part of the skull is it attached ? 
Lying ventrally from the squamosal, and towards 
the median line from the quadrato-jugal, find the 
pterygoid bone, composed of three branching 
projections. With what does each projection ar- 
ticulate ? 

Examine the under side of the skull, and find 
the parasphenoid bone, forming the floor of the 
cranial cavity. What is the shape of this bone ? 
What is its relation to the auditory capsules? 
Find between this bone and the fron to-parietal 
of each side a foramen for the exit of the second 
cranial or optic nerve. Examine the ventral 
and lateral portions of the sphenethmoid, the 
dorsal portion having been previously studied. 
What is the shape of this bone ? Structure ? 
Is the cranial cavity entirely enclosed by bony 
structures ? Does the cranium show any trace 
of segmentation? Compare in this respect with 



FROG 215 

other parts of the axial skeleton. Directly below 
the nasal bone find the palatine bone. What 
is its shape ? Relation to the sphen ethmoid ? To 
the maxilla ? What is the direction of the pala- 
tine bone with regard to the cranial axis ? In 
front of the palatines find the vomers. Ex- 
amine their shape, structure, and articulations. 
Study the position and structure of the vomer- 
ine teeth. 

Study the position, shape, structure, and at- 
tachments of the hyoid apparatus. If the 
parts are not found on the prepared skeleton, 
they may be dissected out on an alcoholic speci- 
men. 

Examine a vertical longitudinal section of the 
skull, made a little to one side of the median line, 
and note the position of the various parts. Note 
especially the septum nasi, which separates the 
nasal chambers, and the foramen, through which 
the first cranial or olfactory nerve passes. 

Eeview all of the bones of the skull, making a 
list of those which enclose the cranial cavity, the 
auditory capsule, and the olfactory capsule. Make 
also a list of those which form the jaws. 

c. The pectoral girdle. — What is its position ? Is it 
a complete girdle? How is it attached to the 
axial skeleton ? Notice that each half of it can 
be divided into two portions, the scapular por- 
tion, extending dorsally from the shoulder-joint, 
and the coracoid portion, extending ventral] y. 
Is the scapular portion of the right directly con- 
nected with that of the left side ? Compare with 
the coracoid portions. Examine the two parts of 



216 THE BIOLOGY OF THE ANIMAL 

the scapular portion, the supra-scapula or carti- 
laginous part, and the scapula or bony part. 
What is the shape of the supra-scapula ? Is it en- 
tirely cartilaginous ? Is it attached by a movable 
or by an immovable connection to the scapula? 
Draw the supra-scapula. What is the shape of 
the scapula? Notice the depression, forming a 
portion of the glenoid cavity, at the ventral end 
of the scapula. What occupies this depression ? 
Draw the scapula. Study the two parts of the 
coracoid portion of the girdle, the posterior part 
or coracoid bone, and the anterior part or clav- 
icle. What is the shape of the coracoid ? Does 
any part of it help to form the glenoid cavity ? 
Draw the coracoid bone. What is the shape of 
the clavicle ? How is it attached to the scapula ? 
Does the clavicle unite directly with the scapula? 
Between the coracoid and the clavicle is the 
coracoid foramen. How is it formed ? What 
is its shape? Examine the sternum, consisting 
of the following parts named from before back- 
ward : episternum, omosternum, epicora- 
coids, sternum proper, and xiphisternum. 
Locate first the epicoracoids, a pair of narrow 
cartilages lying between the inner ends of the 
coracoids and clavicles. Posterior to the inner 
ends of the coracoids lies the sternum proper. 
What is its shape ? Length ? Is it bone or carti- 
lage ? Draw. At the posterior end of the ster- 
num find the xiphisternum. Of what is it com- 
posed ? What is its shape ? Draw. In front of 
the clavicles find the omosternum. Is it attached 
to the clavicles ? What is its shape ? Compare 
with the sternum proper. Draw. Attached to 



FK0G 217 

the anterior end of the omosternum find the epi- 
sternum. Compare in all respects with the xiphi- 
sternum. Draw the episternum. Is the ventral 
portion of the pectoral girdle flexible ? Does the 
girdle as a whole permit of a very great range 
of motion? Of how many pairs of bones does 
the pectoral girdle consist ? Pairs of cartilages ? 
Of how many median bones ? Median carti- 
lages ? 

d. The fore limb. — Examine the right fore limb, and 
note its division into arm or brachium, fore- 
arm or antebrachium, wrist or carpus, and 
hand or manus. Examine the arm - bone or 
humerus. What is its shape ? How is it con- 
nected to the pectoral girdle ? Note the enlarged 
upper end or head of the humerus. How does 
its surface differ from that of the rest of the 
bone ? Extending downward from the head find 
the deltoid ridge. On what part of the hume- 
rus is it ? How is it formed ? How far does it 
extend ? Do you find any other ridges on this 
bone ? Examine the skeletons of several frogs 
of the same size. Are the ridges equally promi- 
nent in all ? How does the lower differ from the 
upper end of the humerus ? In how many direc- 
tions may the humerus be moved ? "Why ? Com- 
pare with your own shoulder -joint. Draw the 
humerus. 

Examine the bone, the radio-ulna, of the fore- 
arm. What is its shape ? Does it appear to be 
composed of two consolidated bones? What is 
the shape of the upper end of the radio-ulna? 
Which is the radius and which the ulna ? Study 



218 THE BIOLOGY OF THE ANIMAL 

the manner in which the radio-ulna articulates 
with the humerus. Note the olecranon process 
back of the elbow-joint. In how many directions 
may the forearm be moved ? Compare with the 
humerus and with your own forearm. Draw the 
bone. 

Study the bones in the wrist, using a lens if 
necessary. How many carpal bones are there? 
How are they arranged ? Of how many motions 
is the frog's wrist capable ? Compare with those 
of your own wrist. How do you account for the 
differences ? What is the natural position of the 
hand of a living frog? How many digits do you 
find in the skeleton of the hand ? Compare with 
the number visible in the hand of the living frog. 
Examine the first bone or metacarpal in one of 
the digits. What is its shape ? Compare all of 
the metacarpals. What differences do you notice ? 
Notice that, in addition to the metacarpal, each 
digit consists of a number of smaller bones, the 
phalanges. How many do you find in each 
digit ? What variations in shape and size of the 
phalanges in a single digit ? Does the thumb or 
pollex differ in structure from the other digits ? 
Of what motions are the digits capable? Draw 
the frog's hand. Compare the structure of the 
frog's hand with your own. What important 
skeletal differences can you distinguish ? 

e. The pelvic girdle. — What is its shape ? In which 
direction does it extend ? Is it attached to the 
axial skeleton more or less firmly than the pecto- 
ral girdle ? What is its relation to the urostyle ? 
Examine the left half, and endeavor to make out 



FROG 219 

that it consists of three consolidated bones, (1) the 
ilium, running nearly parallel to the urostyle, 
and forming with its posterior end more than 
half of the anterior portion of the disk-like mass 
lying between the heads of the thigh-bones; (2) 
the ischium, forming the greater part of the 
posterior half of the disk-like mass ; and (3) the 
pubis, forming the ventral portion of the disk. 
What is the shape of the ilium ? Note the prom- 
inent iliac crest. How far does it extend? 
Where is it widest ? How is the ilium attached 
to the sacrum? Note the acetabulum, into 
which the head of the thigh-bone fits. How is it 
formed ? What is its shape ? Diameter ? What 
is the shape of the ischium ? Of the pubis ? 
Make a drawing showing a side view of the left 
side of the pelvic girdle. 

f. The hind limb. — Compare the thigh-bone or femur 
with the humerus. What differences do you find ? 
Note the nutritive foramen, near the middle 
of the shaft of the femur. What range of motion 
has the femur? Compare the acetabulum with 
the glenoid cavity. Draw the femur. Compare 
the bone, the tibio- fibula, of the leg or crus 
with the bone of the forearm, and note the re- 
semblances and differences. Draw. Compare 
the knee-joint with that of the elbow as to 
structure and range of motion. Note that the 
ankle or tarsus consists of two rows of bones, 
of which two bones, the astragalus on the in- 
side and calcaneum on the outside, unite with 
the tibio-fibula and several other smaller bones. 
Compare the other tarsal and the metatarsal 



220 THE BIOLOGY OF THE ANIMAL 

bones and the phalanges with the correspond- 
ing parts of the fore limb. Look for other nu- 
tritive foramina in the different bones of the 
hind limb. 

What resemblances and differences can you 
trace between the arrangement and structure of 
the frog's skeleton and that of the lobster ? Be- 
tween the motions allowed by the joints ? Com- 
pare the frog's with a human skeleton or with 
pictures of the same. Does the frog have a pa- 
tella or " knee-cap " ? Is there a corresponding 
bone at the elbow ? 

B. — The Muscular System. 

Examine the muscles of an alcoholic specimen 
in a pan containing fifty per cent, alcohol. Keep 
the specimen moist all the time. Remove the 
skin from the entire body, noting the threads 
and bands of connective tissue which bind the 
skin to the underlying parts. In what regions is 
the skin loosely attached ? At what points is it 
most closely fastened ? Can you give any reasons 
for this arrangement of the skin? Wash away 
any coagulated substance, the lymph, which may 
be found lying in the depressions between the 
muscles, and trim away the ragged ends of con- 
nective tissue. Note the groups of muscles in 
the various regions. What distinctions can you 
give between those of the abdomen and those of 
the limbs? What is the color of the muscles? 
Are any of them so thin as to be almost trans- 
parent ? If so, where are they ? How do you 
distinguish one muscle from another ? In study- 
ing each muscle, separate it carefully from its 



FEOG 221 

neighbors by cutting the connective tissue which 
binds them together, and endeavor to make out 
its shape, the direction of its fibres, its origin, its 
attachment, and the motion which it produces. 
Use the articulated skeleton for comparison. 
Make the drawings necessary to show the posi- 
tion and arrangement of the parts. This may 
usually be done by drawing on one side of the 
body the superficial, and on the other side the 
deeper muscles. 

Only the more important muscles are given. 
Examine them in the following order : 

I. The muscles of the trunk. 

Pin the frog down on its back, and notice that 
a certain group of muscles covers the ventral 
side of the body. 

a. The pectoralis, fan -shaped, running from the 
sternum to the shoulder, and consisting of sev- 
eral parts. Where does each part originate ? 
Find one part extending down upon the abdo- 
men. Are all of the parts inserted at the same 
point ? 

b. The rectus abdominis, running from the pu- 
bis. JSTote the linea alba, which separates the 
two recti. Of what is the linea composed ? 
Note also the transverse division of each rectus 
into parts or bellies. How many such parts 
are there? What is the relation of the anterior 
end of this muscle to the pectoralis 1 

Kemove the two muscles just examined and 
find 

g. The oblique muscles, covering the sides of 
the abdomen. The obliquus externus, with 



222 THE BIOLOGY OF THE ANIMAL 

fibres running downward and backward from 
the dorsal surface, and the obliquus interims, 
with fibres running downward and forward. 

Turn the frog over, and study the muscles of 
the dorsal surface. 

d. The depressor niandibuli, a triangular mus- 
cle, posterior to the tympanic membrane. 

e. The latissimus dorsi, a triangular muscle pos- 
terior to the depressor. 

f. The infra-spinatus, partly covered by the latis- 
simus. Raise the supra -scapula, and examine 
the muscles which attach it to the body. 

Clear away the transparent membrane or apo- 
neurosis covering the back, and below it find 

g. The extensor dorsi communis, running from 
the urostyle to the head. Lying under this mus- 
cle look for short muscles connecting the trans- 
verse processes of the vertebrae. 

h. The gluteus, arising from the outer side of the 
posterior portion of the ilium, and running back- 
ward. 

Make fists of all the muscles whose action would 
cause the body to bend (1) downward, (2) upward, 
(3) side wise; (4) would move the head upward; 
(5) would depress the lower jaw ; (6) would move 
the anterior limbs ; (7) would move the posterior 
limbs. 

II. Muscles of the head. 

On the ventral surface of the head find 
a. The mylohyoid, lying directly beneath the skin. 
Remove the mylohyoid and find 

I. The geniohyoid, to one side of the median fine. 



FROG 223 

Notice that posteriorly it divides into two por- 
tions. 

c. The sternohyoid, its anterior end lying between 
the divisions of the geniohyoid. What is the rela- 
tion of the sternohyoid to the rectus abdominis ? 

d. The hyoglossus, uniting in the median line 
with its fellow, and partly covered by the genio- 
hyoid. Study the relation of this muscle to the 
tongue. 

e. The submentalis, at the anterior angle of the 
lower jaw. 

f. The petrohyoids, four small muscles running 
from the auditory capsule to the hyoid bone. 

On the side of the head find 

g. The masseter, lying immediately in front of 
the union of the upper and lower jaws. 

h. The temporalis, running down between the eye 
and the auditory capsule. 

i. The pterygoideus, under the temporalis. 

Make lists of the muscles which (1) increase 
the size of the cavity of the mouth; (2) move 
the tongue ; (3) raise the hyoid bone ; (4) raise 
the lower jaw. 

Carefully cut away the three muscles men- 
tioned above, lay the frog on its back, remove 
the lower jaw and the mucous membrane of the 
roof of the mouth, and find the eye muscles, con- 
sisting of 

j. The levator bulbi, a sheet of muscle lying be- 
tween the eyeball and the mucous membrane. 
"What important use has this muscle ? 



224 THE BIOLOGY OF THE ANIMAL 

Remove the levator bulbi and look for 

h. The recti muscles, four small muscles arising 
together from the inner posterior angle of the 
eye-socket. 

I. The obliqui muscles, two muscles arising from 
the anterior end of the eye-socket. 

m. The retractor bulbi, a cone-shape muscle, aris- 
ing from the angle of the parasphenoid. What is 
the function of this muscle ? 

Make a list of the muscles which (1) raise or 
protrude the eyeball ; (2) depress or lower it ; (3) 
rotate it in the socket. 

III. Muscles of the front limb. 

a. The sternoradialis, a triangular muscle lying in 
front of the shoulder-joint. To what muscle in 
the human body does it correspond ? 

b. The deltoid, a narrow muscle lying in front of 
the sternoradialis. 

o. The triceps brachii, on the upper surface of the 
arm. 

d, The flexor muscles of the forearm and digits, 
covering the inner side of the antebrachium and 
lower surface of the manus. 

e. The extensor muscles of the forearm and dig- 
its, lying on the outer side of the former and 
upper surface of the latter. 

Which of these muscles will draw the arm 
forward? Which bend it? Which straighten it? 
What relation has the deltoid ridge of the hu- 
merus to the attachment of muscles ? 



FROG 225 

IT. Muscles of the hind limb. 

Straighten the hind leg to its fullest extent, lay 
the frog on its back, then examine the muscles on 
the ventral side of the thigh. 

a. The sartorius, a narrow, band-like muscle cross- 
ing the thigh obliquely. 

b. The adductor magnus, lying towards the me- 
dian line from the sartorius, and partly covered 
by the latter. 

c. The adductor longus, on the outer edge of and 
partly covered by the sartorius. 

d. The rectus interims major and the rectus 
internus minor, two muscles forming the in- 
ner border of the thigh. 

Lay the frog on its ventral surface, and on the 
dorsal side of the thigh find 

e. The triceps extensor femoris, forming the 
outer edge of the thigh, and consisting above of 
three parts, of which one, the rectus anticus 
femoris, forms one side of the angle between 
the side of the abdomen and the thigh, and 
another, the vastus externus, appears about 
midway between the first-named muscle and the 
posterior end of the urostyle. 

/. The semimembranosus, lying towards the 
median line from the vastus externus, and marked 
by a tendon running obliquely across the muscle. 

g. The biceps femoris, lying between the vastus 
externus and the semimembranosus. 

h. The pyriformis, passing down between the up- 
per ends of the biceps and the semimembrano- 
15 



226 THE BIOLOGY OF THE ANIMAL 

sus. Separate the rectus internus and the ad- 
ductor magnus, and find between them 

i. The semitendinosus, a muscle with two heads. 
Divide the sartorius transversely and find 

j. The adductor brevis, whose head lies between 
the sartorius and the adductor magnus. 

k. The pectineus, lying along the outer margin of 
the adductor brevis. 

Push aside the vastus internus and find 

I. The ilio-psoas, lying dorsally from the adductor 

brevis. 
m. The quadratus femoris, posterior to the 

gluteus. 

n. The obturator, towards the median line from 
the quadratus femoris. 

Which of the above-named muscles pull {flex) 
the thigh ? Which draw {extend) it backward ? 
On the leg find 
o. The gastrocnemius, the muscle of the calf of the 
leg. Note its large tendon, the tendo Achillis. 

p. The tibialis anticus, along the outer margin of 
the leg. 

q. The tibialis posticus, lying along the inner 
margin of the gastrocnemius. 

r. The peroneus, lying between the tibialis anticus 
and the gastrocnemius. 

s. The extensor cruris brevis, along the anterior 
margin of the tibialis anticus. 

Examine the muscles and tendons of both sur- 
faces of the foot. 

Which of the leg muscles are extensors ? Flex- 



FROG 227 

ors ? Which muscles flex the foot ? Extend the 
foot ? What reasons can you give for the large 
size of the thigh muscles ? Of the gastrocnemius ? 
For the great difference in size between the mus- 
cles of the anterior and those of the posterior 
limb? When the frog's leg is flexed upon the 
thigh, does it lie in the same position as the 
human leg ? 

Compare the arrangement of the principal mus- 
cles of the frog with the corresponding muscles 
of the human body, as shown on charts, ana- 
tomical plates or on a manikin. 
C. — The Digestive System. 
I. The mouth-cavity. 

Pull down the lower jaw and open the mouth 
to its widest extent. 

What is the shape of the mouth-cavity ? Can 
it be enlarged ? If so, in what directions ? What 
external organs mark the posterior boundary of 
the mouth-cavity ? Are there any lips ? What is 
the color and texture of the mucous membrane 
lining the cavity ? Can the position of the eyes 
be determined by an examination of the roof of 
the mouth % Press upon the external surface of 
the eyeball. What change takes place in the 
mucous membrane of the roof of the mouth ? 

Examine the roof of the mouth and find the 
following structures : 
a. The maxillary and vomerine teeth. — These 
were examined in the skeleton. Note again their 
position, arrangement, prominence, etc. 

h. The posterior nares. — How many are there? 
What is their position with regard to the anterior 



228 THE BIOLOGY OF THE ANIMAL 

nares ? To the vomerine teeth ? What is their 
shape ? Pass a bristle through from the external 
openings. 

Look back, near the union of the two jaws, 
and find 

e. The openings of the Eustachian tubes. — 

What is their exact position ? How do they com- 
pare in size with the posterior nares? Pass a 
bristle into one of the openings, then remove the 
tympanic membrane of the same side. Into what 
cavity does the Eustachian tube lead ? 

Make a sketch of the roof of the mouth. Ex- 
amine the floor of the mouth. 

Do you find that any part of the floor is firmer 
than the rest? If so, where is this part, and to 
what is the firmness due ? 

d. The tongue. — Does it entirely cover the floor of 
the mouth ? What is its shape ? Size ? Where 
is it attached? Can the tip of the tongue be 
thrust out of the mouth ? What is the character 
of the upper surface of the tongue ? Note the 
papillae covering this surface. Compare the 
lower with the upper surface. What reasons 
can you give for the shape of the posterior end ? 

Back of the tongue find an opening, 

e. The glottis. — What is its shape? What is the 
nature of its margin ? What is the arrangement 
of the mucous membrane on each side of the 
glottis ? 

Pass a stiff guarded bristle back of the glot- 
tis, and note that it passes into another opening, 
which leads into the oesophagus. 



FROG 229 

In some frogs (males) the opening of a vocal 
sac may be found on each side between the edge 
of the tongue and the lower jaw. 

II. The alimentary canal. 

Lay the frog on its back and dissect away all 
of the muscles, bones, etc., covering the ventral 
side of the body from the pubis to the jaw, being 
careful not to injure the underlying parts. Leave 
the glottis and trachea in position. Note the 
manner in which the various organs — heart, liver, 
lungs, intestine, etc. — are closely packed. Insert 
a fine-pointed blowpipe — e. g., a glass tube drawn 
out to a tapering end with rounded edge — into 
the glottis and inflate the lungs. This will define 
their position. Do likewise to the bladder by in- 
serting the end of the blowpipe into the opening 
of the cloaca. Note the heart, almost surrounded 
by the lobes of the liver. Kemove the heart, and 
at present pay attention only to the digestive or- 
gans. 
a. The liver. — What is its position? Shape? 
Color ? Of how many lobes does it consist ? What 
difference in their shape and size? What is its 
position relative to the heart ? To the lungs ? Do 
you find a partition or diaphragm completely 
separating the cavity in which the heart and 
lungs lie from that in which the liver and other 
digestive organs are found? Turn the liver over 
towards the left (the frog's right) side, and note 
the oesophagus leading into the stomach. 

h. The oesophagus. — In what direction does it 
run ? What is its shape ? Color ? Diameter ? 
What is its relation to the heart ? To the lungs ? 



230 THE BIOLOGY OF THE ANIMAL 

To the liver? How is the oesophagus held in 
place ? Carefully pinch the oesophagus with the 
fine forceps. What is the nature of the wall? 
How do you distinguish the boundary between 
the oesophagus and the stomach ? With the scis- 
sors make on the ventral side of the oesophagus a 
transverse slit, half severing it from the stomach, 
then from this slit make a longitudinal cut ex- 
tending towards the mouth, thus laying open the 
oesophagus. Spread back the two flaps, remove 
the contents, if any, and examine the wall of the 
oesophagus. Do you find the lining membrane 
or mucous membrane arranged at all differ- 
ently from the outer wall ? 

c. The stomach. — On which side of the body does 
it lie ? What is its shape ? What is its relation to 
the liver? Note the membrane or mesentery 
which holds the stomach in place. Lay open the 
stomach by a cut extending along its left margin. 
Does its wall differ in any way from that of the 
oesophagus? Notice particularly the arrange- 
ment of the lining or mucous coat. Does this 
differ at all in stomachs which are distended with 
food and those which are empty ? 

Leading from the posterior end of the stomach 
find the intestine, consisting of a coiled portion, 
the small intestine, and a straight portion, the 
large intestine. 

d. The small intestine. — What is its position? 
Shape ? Color ? How is it arranged ? Are its 
various coils connected ? If so, by what means ? 
How does it compare in diameter with the oesoph- 
agus ? With the stomach ? Is the wall of the 



FKOG 231 

small intestine thin and flexible or thick and 
rigid? What is its length? The upper, nearly 
straight portion of the small intestine is called 
the duodenum ; the lower, coiled portion is the 
ilium. Split open the small intestine, and com- 
pare its inner wall with that of the stomach. 
Note the shaggy appearance of the lining of the 
duodenum. Examine the transverse folds or in- 
testinal valves in the ilium. Look for the valve, 
the pylorus, between the stomach and the duo- 
denum. 
e. The large intestine. — What is its position in 
the body ? Shape ? At what point on its sur- 
face does the small intestine unite with it ? How 
is it situated with regard to the urinary bladder ? 
Split the pubic bone apart, remove the two hind 
legs, and trace the large intestine down to the 
point where it unites with the cloaca. Examine 
the inside of the large intestine, and note the valves 
at the point of entrance of the small intestine. 

/. The cloaca. —What is its position? Length? 
Structure of its walls ? 

Find, lying partly in the loop between the 
stomach and the duodenum, 

g. The pancreas. — What is its relation to the 
stomach ? To the liver ? What is its texture ? 
Shape? Color? 

Spread apart the lobes of the liver and find a 
small yellow sac, 

h. The gall-bladder.— Between which lobes does 
it lie? What is its position with regard to the 
heart? Look for the ducts, the cystic ducts, 
entering the gall-bladder from the liver. 



232 THE BIOLOGY OF THE ANIMAL 

Endeavor to trace the course of the common 
bile duct, which leads from the gall-bladder to 
the duodenum. This may be done by squeezing 
the gall-bladder, thus forcing some of its contents 
into the duct. What is the relation of the pan- 
creas to the common bile-duct ? Examine the in- 
side of the duodenum for the opening of the gall- 
bladder. 

Lying in the middle line, and to one side of 
the large intestine, find a small red body, 

i. The spleen. — What is its shape? Size? To 
what is it attached ? 

Cut the oesophagus across, as close as possible 
to the mouth, and carefully remove all of the di- 
gestive tract from the abdominal cavity by cut- 
ting the mesentery, which holds the parts in 
place. Uncoil the intestine in the same manner. 
Leave the large intestine attached to the cloaca. 
Do not disturb the other organs. Straighten the 
whole alimentary canal and measure its length. 
How many times longer than the body is it? 
How far from the anterior end do the digestive 
glands — liver and pancreas — pour their secretions 
into the canal ? Note the pigmented membrane 
or peritoneum' which lines the body-cavity or 
pleuro-peritoneal cavity. Note also that it is 
this membrane which forms a sling in which the 
stomach and other parts of the digestive system 
are held. By what is this sling supported ? 
Make a diagram of the entire alimentary canal. 

D. — The Respiratory System. 

Passing downward from the glottis find 
a. The larynx. — What is its position with regard to 



FROG 233 

the glottis ? To the lungs ? What is the struct- 
ure of its walls ? 

Cut away the anterior wall of the larynx and 
note, leading to each lung, 

h. The bronchus. — What is the shape of the bron- 
chus ? Length ? Structure ? 

c. The lungs. — What position do the lungs occupy 

with regard to the larynx? The heart? The 
liver? How are they held in place? What is 
the shape of the lung when collapsed? When 
distended ? How much larger than the former is 
the latter ? What is the texture of the wall of 
the lung ? On the distended lung look for the 
pulmonary artery, running the entire length 
of the organ. Distend one of the lungs, then re- 
move it by cutting through the bronchus, and 
with a pair of fine scissors inserted into the 
bronchial opening slit the lung along one side 
to the end, and spread out the organ under water. 
What is the structure of the lung? Note the 
network formed by muscles, connective tissue, 
and blood-vessels. 

d. The vocal cords. — Open the glottis and look for 

two narrow bands of tissue stretched vertically 
and running from before backward. 
Make a diagram showing the arrangement of the res- 
piratory organs. Draw a collapsed and a distended 
lung to the same scale. Make a drawing showing a 
cross -section of a distended lung; another drawing 
showing the network on the interior. 

e. The vocal sacs. — Select a male frog and examine 

the vocal sacs. What is their position ? Shape ? 



234 THE BIOLOGY OF THE ANIMAL 

To what extent may they be inflated ? Are they 
directly connected with the lungs ? 

E. — The Urino-genital System. 

After the digestive organs have been removed, 
there will be found in both sexes two elongated, 
dark-red bodies lying on each side of the verte- 
bral column. These are 

a. The kidneys. — What is their position with regard 

to the large intestine % To the spleen ? What is 
their shape ? How long are they ? What is their 
relation to the peritoneum ? 

On the surface of each kidney find a yellow- 
ish band, 

b. The adrenal body. — What is its shape? How 

much of the length of the kidney does it cover ? 
Of the width ? How intimately is it connected 
to the kidney ? Draw a kidney with its adrenal 
body. 
Leading from the kidney find a white tube, 

c. The ureter. — From what part of the kidney does 

it arise ? Is it straight or coiled ? What is its 
length ? Into what does it lead ? Open the clo- 
aca and endeavor to find the opening of the ure- 
ter. In the male this duct carries the secretion 
of the testes and is, hence, a urinogenital duct. 
In such a specimen examine the lower end of the 
duct for a dilated glandular portion, the vesicula 
seminalis. 

d. The bladder. — What is its position? What is its 

relation to the large intestine? Shape? Size? 
Texture of its wall ? Is it directly connected with 
the ureters? How is it connected with the clo- 



FROG 235 

aca ? How held in place % Make a sketch of the 
bladder. 

In male specimens look near the kidneys for 
two yellowish bodies, 

e. The testes. — How are they situated with regard 
to the kidneys ? What is their shape ? Size ? 
Color? How are they held in place ? Look for 
the ducts or vasa efferentia, which run from 
the testes to the kidneys. At what point do these 
ducts leave the testes ? Where do the ducts enter 
the kidneys? How many such ducts has each 
testis ? 

On the anterior end of each testis find a series 
of fringe-like lobes forming 

f. The fat bodies. — What is their exact position? 

Shape ? Color ? How many lobes has each ? 
Make a sketch of a testis and the fat bodies. 

In female specimens look, in quite the same 
position as the testes occupy in the male, for 
dark-gray or black bodies, 

g. The ovaries. — Compare them in shape, size, color, 

structure, etc., with the testes. When the ovaries 
contain eggs which are approaching maturity, the 
latter look like small shot, which distend the ova- 
ries until they at times fill a very large part of 
the abdominal cavity. What is the shape of the 
eggs ? Color ? 

In the neighborhood of these glands look for 
coiled white tubes, 

h. The oviducts. — How do they compare in size 
with the ureters ? Carefully remove one of the 
oviducts, beginning at the posterior end, and note 



236 THE BIOLOGY OF THE ANIMAL 

its various coils and attachments. Endeavor to 
make out the following parts : a posterior, thin- 
walled portion, the uterine segment, near the 
kidney; a middle portion, or glandular seg- 
ment, which is very much coiled ; and an ante- 
rior, thin-walled portion, which passes back of the 
lung and opens into the pleuro-peritoneal cavity 
just behind the root of the lung. How long is 
the oviduct ? Does it in any part of its course 
unite directly with the ovary? Look for the 
opening of the oviduct into the cloaca. 
Make a diagram of the arrangement of the various 
parts of the urino-genital system. 

F. — The Circulatory System. 

Kill with chloroform the largest obtainable 
frog, fasten it down on its back in a dissecting- 
pan, and open the skin by incisions extending, one 
along the entire length of the median ventral line, 
one along the middle line of each limb, one from 
the pubis around the top of each thigh, in the 
angle between the thigh and the body, and an- 
other following the lower jaw-bone on each side. 
Carefully turn back the flaps thus formed, pay- 
ing particular attention to the points where blood- 
vessels issue from the underlying parts to ramify 
on the skin. Cut through the abdominal muscles 
a little to one side of the median line ; cut through 
the sternum, being careful not to injure the under- 
lying blood-vessels ; and pin back the flaps. In 
frogs dissected immediately after being chloro- 
formed the heart will be found beating. 

If desired, the vascular system may be injected 
from the heart; but this is not necessary, as the 



FEOG 237 

principal vessels are found after death to be plain- 
ly visible on account of the accumulation of blood 
in them. 

I. The external anatomy of the heart. 

What is its position with regard to the sternum ? 
Can you give any reasons for this? What is the 
position of the heart with reference to the liver ? 
The lungs ? Notice the membranous sac or peri- 
cardium which surrounds the heart. What is its 
texture? Color? Does it fit closely around the 
heart? Cut open the tip of the pericardium and 
note the contained fluid, the pericardial fluid. 
What is its color? Is it abundant? Split open 
and remove the pericardium. At what point is it 
attached to the heart ? Is it attached to any other 
organs ? What is the shape of the heart? Length? 
Breadth? What variations in color in different 
parts? Notice the light-colored apex, the ven- 
tricle. Towards which end of the body is the 
apex of the heart directed ? How much of the 
entire heart does the ventricle form? At the 
left (really right) side of the base of the ven- 
tricle, as you look at it, find a short, light-colored 
tube, the truncus arteriosus, which at its ante- 
rior end divides into two branches, the aortic 
arches. On each side of the truncus is seen an 
auricle. How much of the heart do the auricles 
form? How do they differ in color, shape, and 
size, from the ventricle ? With the tip of the for- 
ceps carefully press the wall of one of the auri- 
cles. How does it compare in firmness with that 
of the ventricle ? What is the shape of the trun- 
cus ? How long is it ? What is its diameter ? In 



238 THE BIOLOGY OF THE ANIMAL 

which direction does it extend ? Examine its sur- 
face with a lens. Do you find blood-vessels in its 
wall? How do you distinguish the aortic arches 
from the surrounding parts ? In what direction 
do the arches run ? Make a drawing of the heart, 
showing all of the parts thus far examined. 

Cautiously bend the heart backward by raising 
its tip. On the dorsal side of the heart find the 
sinus venosus. What is its shape ? How is it 
attached to the heart ? How much of the latter 
does it cover? What is the texture of its wall? 
Find three veins, the venae cavae, one posterior 
and two anterior, leading into the sinus. At 
what points do they enter? Dissect away the 
ventral wall of the sinus and look for the open- 
ing, the sinu-auricular aperture, by which it 
communicates with the right auricle. What is 
the position of the aperture ? Shape ? Note the 
lip-like folds or valves which guard the opening. 

II. The veins. 
a. The anterior venae cavae. — On either the right 
or left side trace the caval vein of that side by 
carefully dissecting away the muscles and mem- 
branes. It will be seen to be formed by the 
union of three veins — one, the subclavian, com- 
ing from the direction of the fore-limb ; another, 
the external jugular, from the outer edge of 
the hyoid bone ; and the third, the innominate, 
coming in between the other two. Which of 
these veins is the largest? Trace forward the 
two branches of the external jugular vein. One 
branch, the lingual vein, comes from the 
tongue and the floor of the mouth ; the other 



FROG 239 

branch, the inferior maxillary vein, comes 
from the margin of the lower jaw. What is the 
course of each vein? Find the two branches 
which unite to form the subclavian vein ; one, the 
brachial vein, comes from the fore limb, and 
the other, the musculo-cutaneous vein, comes 
from the skin and muscles of the side and back 
of the body. The branches of the innominate 
vein are the internal jugular, which appears 
immediately behind the angle of the jaw, and the 
subscapular vein, lying among the muscles of 
the shoulder. From what parts of the body does 
the blood come which enters the sinus venosus 
through the anterior venae cavae ? 
Make a diagram of the veins which communicate with 
the anterior venae cavae. 

h. The posterior vena cava.— Displace the ali- 
mentary canal by cutting across the oesophagus, 
and turning the entire system downward over the 
pubis, cutting the mesentery wherever necessary. 
In which direction does this vein run ? How does 
it compare in diameter with the anterior venae 
cavae ? Trace the vein towards the posterior 
end of the body and find coming from the liver 
the hepatic veins. How many are there ? At 
what point do they enter the vena cava? Far- 
ther back find the renal veins, entering from the 
kidneys along with the genital veins from the 
ovaries or testes, as the case may be. How many 
renal veins do you find? How many genital? 
Which are the larger? 
Make a diagram of the posterior vena cava and the 
connecting veins. 



240 THE BIOLOGY OF THE ANIMAL 

c. The pulmonary veins. — Turn the heart for- 
ward and find coming from each lung a small, 
dark-colored vein. What is their position with 
regard to the sinus venosus ? Which cavity of 
the heart do these veins enter? Do they unite 
before entering the heart? 

Make a drawing showing the relation of the pulmo- 
nary veins to the heart. 

d. The anterior abdominal vein. — Examine the 
median ventral line of the body. What is the 
course of this vein ? Note its branches, the epi- 
gastric veins. How are they arranged? How are 
they situated with regard to the abdominal mus- 
cles ? Trace the anterior abdominal vein back to 
the pubis, and note that it is formed by the union 
of two short veins, the pelvic veins. Separate 
the muscles of one of the thighs and find the two 
veins, femoral and sciatic, which unite to form 
the pelvic vein. The femoral vein may be distin- 
guished by its larger size. Does this vein com- 
municate with the sciatic? Trace the femoral 
vein to the space back of the knee-joint, and note 
that this vein is a continuation of another, the 
posterior tibial vein, which arises from branch- 
es covering the upper surface of the foot. At 
the posterior end of the anterior abdominal vein 
find the vesical vein, coming from the bladder. 
Look also for the parietal veins, which come 
from the ventral side of the body-wall. On the 
truncus arteriosus find another branch, the car- 
diac vein. At the forward end of the anterior 
abdominal vein find its branches, which run to the 
liver. Does this vein communicate directly with 
the heart ? 






FROG 241 

Make a diagram showing the vein and its branches. 

e. The hepatic portal vein. — Look for this vein 
near the point where the anterior abdominal vein 
sends its branches to the liver. Endeavor to find 
the branches — gastric vein, intestinal vein, 
and sometimes splenic vein — by whose union 
this vein is formed. 
Make a diagram of the hepatic portal vein and its 
branches. 

f. The renal portal vein. — This vein is found en- 
tering the outer side of the kidney. Trace it 
backward to its branches, the sciatic vein from 
the thigh and the dorso-lumbar vein from the 
back, and, in female, the oviducal veins from 
the ovary. 
Make a diagram of the renal portal vein and its 
branches. 

III. The arteries. 

Take a fresh specimen and prepare it as di- 
rected for the study of the veins. The arteries 
may be distinguished as being of lighter color and 
having thicker walls than the veins. Distend the 
oesophagus by thrusting into it a slender pencil, 
a glass rod, or a roll of paper. 

a. The aortic arches. — Trace forward the right 
and left branches of the truncus arteriosus, clean- 
ing away the muscles and connective tissue, and 
notice that each branch subdivides into three sets 
of tubes which form the aortic arches. These are 
the carotid arch, which is the anterior of the 
three ; the systemic arch, which lies between the 

other two, and the pulmo-cutaneous arch. How 

16 



242 THE BIOLOGY OF THE ANIMAL 

far from the heart do the arteries arise ? How far 
apart? Trace the anterior artery, the common 
carotid, to the point where it subdivides into the 
external carotid or lingual artery and the 
internal carotid artery. What course does each 
take ? What is the position of the lingual artery 
with regard to the external jugular vein ? Of the 
internal carotid artery with reference to the in- 
ternal jugular vein ? Near the base of the lingual 
artery find a small swelling, the carotid gland. 
Make a diagram of the carotid or aortic arch and its 
branches. 

Study next the systemic arch. Trace either half, 
dor sally and posteriorly, to the anterior end of the 
kidney, where it unites with the corresponding 
artery from the other side and forms the dorsal 
aorta. Still farther back it divides into the 
iliac arteries. How long is the aortic arch ? 
How long is the dorsal aorta ? At what point do 
the iliac arteries arise ? In which direction do they 
run ? Given off by the aortic arch find the sub- 
clavian artery. In which direction does it run ? 
What is its relation to the subclavian vein ? Find 
also the vertebral artery. What is its position? 
Note its branches. How are they arranged ? How 
many are there? To what parts do they run? 
At or near the point where the dorsal aorta 
arises look for the stump of a branch, the cceli- 
aco-mesenteric artery, which runs to the ali- 
mentary canal. Trace the branches of this blood- 
vessel to the various digestive organs. Farther 
back find the urino-genital arteries. From 
what part of the dorsal aorta do they arise ? How 
many are there ? Eunning to the large intestine 



FROG 243 

find the inferior mesenteric artery. Look 
also for the splenic artery. Trace one of the 
iliac arteries back to the sciatic artery, which 
eventually divides into peroneal and tibial ar- 
teries. 
Make a diagram of the arrangement of the blood- 
vessels which communicate with the heart by means of 
the systemic arch. 

Examine the pulmo - cutaneous arch, and trace its 
branches, the cutaneous artery, to the skin, and the 
pulmonary artery, to the surface of the lung. Draw 
this arch and its branches. 

Compare the above arches as regards the extent of 
the distribution of their branches. 

IV. The internal anatomy of the heart. 

In frogs killed with chloroform it will be 
found that the heart is distended with blood. 
The heart of any of the specimens thus far ex- 
amined may be used, or one may be especially 
prepared by killing a frog with chloroform, open- 
ing the body so as to expose the heart, and plac- 
ing the entire specimen in alcohol. In a day 
or so remove the heart by cutting it away from 
the lungs and severing its attached blood-vessels 
at a sufficiently remote distance from the organ. 
Examine its external anatomy again so as to get 
the various regions of the organ clearly in mind. 
Select three small bristles of different colors, and 
gently thrust one of them into the carotid, an- 
other into the aortic, and the third into the 
pulmonary arch. Then fasten the heart down, 
dorsal side uppermost, in a dissecting -pan by 
thrusting small pins through the apex of the ven- 



244 THE BIOLOGY OF THE ANIMAL 

tricle and through some of the blood-vessels. 
With sharp, fine scissors carefully cut away 
enough of the ventral surface of the ventricle, 
truncus arteriosus, auricles, and aortic arches to 
expose their cavities. With a stream of water 
from a pipette wash the clotted blood out of the 
cavities. The study of certain points will be 
facilitated if the preparation be placed in a deep 
watch-glass- containing fifty per cent, alcohol, and 
held near a window where the light may shine 
through the membranes. Examine the ventri- 
cle. What is the character of its wall? How 
thick is it ? What is its color ? How does it dif- 
fer from the walls of the auricles ? From that 
of the truncus arteriosus? Notice that the 
cavity of the ventricle is undivided. On the right 
of the preparation look for the auriculo - ven- 
tricular aperture. What is its shape? Into 
what does it open ? Look for the two auriculo- 
ventricular valves. How are they connected 
with the walls of the ventricle? Between the 
two auricles find the inter-auricular septum. 
What is its structure? In which direction does, 
it extend? What is its position with regard to 
the truncus arteriosus? To the auriculo- ventric- 
ular aperture ? In the right auricle, near the sep- 
tum, look for the opening of the sinus venosus, 
the sinu-auricular aperture. Near the top 
of the left auricle find close to the septum the 
aperture of the pulmonary veins. Examine 
the truncus arteriosus and note its connection 
with the ventricle. From what part of the latter 
does the truncus start ? Note the longitudinal 
valve which divides the truncus into two parts. 



FROG 245 

At what points clo the carotid, aortic, and pul- 
monary arches unite with the truncus ? 
Make a drawing illustrating the structure of the 
heart and the connecting blood-vessels. 

V. The lymph hearts. 

The study of the lymphatic system is too diffi- 
cult for the beginner. The posterior lymph 
hearts, however, are easily found by dissecting 
away the skin on each side at th,e posterior end 
of the urostyle. The pulsations of these organs 
are sometimes visible through the skin in the 
living frog. It is best to look for them imme- 
diately after the frog's death, before they cease 
moving and partly collapse. 

G. — The Nervous System. 

Select a large specimen which has lain for two 
or three days in seventy-five per cent, alcohol, 
portions of the skull and vertebral column hav- 
ing been removed in order to permit the alcohol 
to penetrate to the enclosed organs. Clean away 
all of the dorsal muscles on each side of the ver- 
tebral column, from the sacrum to the base of 
the skull. Remove the roof of the skull by in- 
serting the points of fine, strong scissors through 
the membrane covering the space between the 
base of the skull and the first vertebra, and mak- 
ing parallel incisions passing forward on each 
side from the occipital region to the nostrils. Be 
exceedingly careful not to run the points of the 
scissors into the brain. As rapidly as the skull 
is loosened behind, lift it up with forceps and 
turn it forward in order to see where to cut. Do 



246 THE BIOLOGY OF THE ANIMAL 

not injure the pigmented membrane covering the 
brain. When the roof of the skull has been re- 
moved, cut away in the same manner the tops of 
the neural arches and urostyle. Prepare another 
specimen by fastening it down on its back and 
removing all of the viscera. 

I. General structure. 

a. Compare the two specimens and note that the 
nervous system consists of two portions, a central 
portion, enclosed in the cerebro-spinal canal, 
and a peripheral portion, consisting of nerves 
running to various parts of the body. Notice also 
that the central nervous system is divisible into 
two regions, an anterior portion, the encephalon 
or brain, lying in the skull, and a posterior por- 
tion, the myelon or spinal cord, lying in the 
neural canal. How do these two regions conrpare 
in length ? In diameter ? Are they distinctly 
separated from one another? How do you dis- 
tinguish the one from the other ? 

h. The membranes. — Examine the pigmented mem- 
brane, the pia mater, which covers these parts of 
the nervous system. What is its color ? Is it even- 
ly colored? If not, where are there noticeable 
collections of pigment cells ? Does the pia mater 
cover all parts lying within the cerebro-spinal 
canal ? Note the large blood-vessel running along 
the middle of the dorsal surface of the pia mater. 
Examine the membrane with a lens, and note the 
numerous blood-vessels. Divide the pia mater 
immediately behind the posterior lobes of the 
brain, and examine that part of it which, form- 
ing a choroid plexus, covers a triangular cav- 



FKOG 247 

ity, viz., the fourth cerebral ventricle, immediately 
below the pia. Is the choroid plexus thicker than 
other parts of the membrane ? Is it more vascu- 
lar ? Lining the wall of the neural canal look for 
another membrane, the dura mater. Is it col- 
ored like the pia ? Is it as thin and vascular as 
the latter ? 

II. The central nervous system, 
a. The brain. — Examine its dorsal surface. What 
is its general shape ? Is it bilaterally symmetri- 
cal ? Is its surface smooth, or marked with ridges 
and furrows, i. <?., convoluted ? What is its po- 
sition with reference to the eyes ? Lying between 
the latter organs find on the brain two elongated 
masses, the cerebral hemispheres, at the an- 
terior end of each of which is an olfactory 
lobe, from which proceeds forward a nerve, the 
olfactory nerve. What is the shape of the ce- 
rebral hemispheres ? Why are they called " hemi- 
spheres " ? How long are they ? How wide ? Are 
they connected ? If so, how ? How much of the 
brain do they form ? Are the olfactory lobes 
sharply separated from the cerebral hemispheres ? 
Are the lobes connected with each other? What 
is their shape? How do they compare in size 
with the hemispheres? Immediately behind the 
hemispheres find a diamond-shaped area, the tha- 
lamencephalon. Note that the pia mater here 
forms another choroid plexus. Near the middle 
of the roof of the thalamencephalon find the re- 
mains of the stalk of the pineal gland, the gland 
probably having been torn away when the skull 
was removed. Cut away the choroid plexus and 



248 THE BIOLOGY OF THE ANIMAL 

beneath it find a cavity, the third ventricle, in 
the thalamencephalon. Notice the thickened sides 
of the thalamencephalon which form the optic 
thalami. Posterior to the thalamencephalon find 
the two optic lobes. How do they compare in 
size with the cerebral hemispheres ? With the 
olfactory lobes? What is their shape % Behind the 
optic lobes find a transverse band, the cerebel- 
lum. What is its shape ? Back of the cerebel- 
lum comes the medulla oblongata, which grad- 
ually tapers into the spinal cord. What is the 
shape of the medulla \ Can you distinguish a di- 
viding line between the medulla and the cord ? 
In the medulla find a cavity, the fourth ventri- 
cle. Is the ventricle continued under the cere- 
bellum ? Does it extend back into the spinal cord ? 
Draw the dorsal surface of the brain. 

With a sharp scalpel or scissors cut off horizon- 
tally the upper surface of the brain, thus exposing 
the cavities or ventricles. Notice that the brain 
is hollow, with its walls variously bent and folded. 
Notice also that some of the cavities lie in the 
median or axial line, and that the others are 
paired lateral outgrowths of the former. Do the 
walls of the parts of the brain vary in thickness 
in different regions % Begin at the fourth ventri- 
cle and trace forward the system of cavities. 
What parts of the brain form the walls of this 
ventricle ? Find the duct, the iter a tertio ad 
quartum ventriculum or the aqueduct of 
Sylvius, which leads from the fourth ventricle 
forward to the third ventricle. What is the rela- 
tion of this duct to the optic lobes % Are the latter 
hollow ? If so, what is the shape of the cavities ? 



FROG- 249 

Do the cavities communicate with the duct? What 
is the shape of the third ventricle? Note the 
lateral ventricles, one in each of the cerebral 
lobes. What is their shape ? Do they extend for- 
ward into the olfactory lobes ? Look for an open- 
ing, the foramen of Monro, leading from the 
third into each of the lateral ventricles. What is 
its position ? 
Make a diagram showing the cavities of the brain. 

Make an incision separating the olfactory nerves 
from the lobes ; gently lift up the anterior end of 
the brain, and bend the latter backward until it 
rests upon the spinal cord. In doing so cut each 
of the nerves passing out through the cranial 
walls. The ventral surface of the brain will then 
be exposed. Note the pia mater with its blood- 
vessels. Remove the pia. Can you trace the 
ventral roots of the olfactory nerves run- 
ning back upon the olfactory and cerebral lobes ? 
Are the cerebral lobes entirely separated at any 
point on their ventral surface ? Between the bases 
of the latter lobes find a rounded surface, the 
lamina terminalis. Extending around the pos- 
terior portion of the lamina find the roots of the 
optic nerves, connected in the middle line by the 
optic chiasma. Running dorsally from the chi- 
asmaon each side is an optic tract. What is the 
appearance of the optic lobes as seen from below ? 
What is their position with regard to the optic 
nerves, chiasma, and tracts ? Immediately behind 
the chiasma find a lobed body, the tuber cine- 
reum. What is its shape ? What is its relation 
to the thalamencephalon ? Directly back of the 
tuber find the stalk, the infundibulum, of the 



250 THE BIOLOGY OF THE ANIMAL 

pituitary body or hypophysis. What is the 
shape of the latter ? Color ? Size as compared 
with the tuber ? 
Draw the ventral aspect of the brain. 

Examine another brain which has been hard- 
ened and removed from the skull, and note the 
various parts as seen from the side. Draw the 
lateral view of such a preparation. Make verti- 
cal sections, both transversely and longitudinally 
through a brain and study the sections in order. 
Draw. 
b. The spinal cord. — Study carefully the shape of 
the spinal cord as seen from above/ Notice the 
enlargements, brachial and lumbar, at the 
points where the nerves for the limbs originate. 
Note that the posterior end of the cord tapers 
into the filum terminale, which extends into the 
canal of the urostyle. Does the cord fill the neu- 
ral canal ? Note this particularly with reference 
to the posterior portion of the neural canal where 
the end of the cord, together with the roots of 
some of the nerves which run to the hinder parts 
of the body, forms the cauda equina. Look for 
the dorsal fissure, which extends along the 
cord. How far can you trace it? Examine a 
cord which has been removed from the spinal 
canal. Can you find a ventral fissure? Do these 
correspond to parts seen on the brain? Examine 
a transverse section of a cord and find the cen- 
tral canal. To what does this correspond in 
the brain? Note also the roots of the spinal 
nerves. 
Make the drawings necessary to show the structure 
of the spinal cord. 



FROG 251 

III. The peripheral nervous system. 

With the experience which he has now had in 
dissecting muscles and in tracing blood-vessels, 
the student ought to be able to trace the follow- 
ing nerves, and to distinguish their more striking 
features ; consequently only the names, origin, and 
termination of the parts of the peripheral nervous 
system will be given. 

a. The spinal nerves. 

Examine a spinal cord and note the connection 
of each of the spinal nerves to the spinal cord by 
means of an anterior or ventral and a posterior 
or dorsal root. In which direction do these 
roots run ? Is there any difference in this re- 
spect between the roots of the anterior and those 
of the posterior nerves? Trace the roots to the 
intervertebral foramina. Do the roots unite in- 
side the spinal canal ? Turn the frog over on 
its back, and note the nerves lying as white cords 
on each side of the vertebral column. At their 
point of issue from the spinal column they are 
covered by a yellowish - white deposit of lime 
secreted by the periganglionic glands. This 
may be neatly removed by gently teasing with 
the point of a fine, sharp scalpel the pigmented 
membrane which covers the limy patches, then 
with a pipette carefully placing on each patch a 
drop of dilute nitric or hydrochloric acid. The 
acid dissolves the lime without injuring the sur- 
rounding tissues. 

Under the patch may be found the point of 
union of the two roots. Towards the cord from 
this point look on the posterior root for the gan- 



252 THE BIOLOGY OF THE ANIMAL 

glion. How do you distinguish it? What is its 
shape? Size? Color? Immediately after the 
two roots unite, the nerve divides again into two 
branches, one of which runs dorsally, the other 
ventrally. How do the two branches compare in 
size ? The dorsal branches run mainly to the 
muscles and skin of the back. 

Trace, in order, the following ventral branches 
of the spinal nerves. 

These nerves receive their number from the 
number of that vertebra back of which they leave 
the neural canal. 

1. The first spinal nerve or hypoglossal runs 
forward from behind the first vertebra to the 
tongue, passing in its course under the mylo- 
hyoid muscle and into the substance of the ge- 
niohyoid. 

2. The second and third spinal nerves unite 
to form the brachial nerve. This gives off a 
branch to the shoulder muscles and then con- 
tinues down the arm to form the radial and 
ulnar nerves. 

3. The fourth, fifth, and sixth spinal nerves 
run to the body-wall and to the skin. 

4. The seventh, eighth, and ninth spinal 
nerves unite to form the sciatic plexus, from 
which arises the sciatic nerve, which contin- 
ues down the hind limb and divides into the 
tibial and peroneal nerves. 

5. The tenth spinal nerve or coccygeal 
emerges from a foramen in the urostyle, and 
sends branches to the cloaca, bladder, and sur- 
rounding parts. 

Compare all of these nerves and note the striking dif- 



FROG 253 

ferences in size, color, direction, branches, etc. Make a 
diagram of the spinal nerves as seen from the ventral side. 

h. The Sympathetic System. 

This is best seen in a specimen from which the 
internal organs have been removed from one half 
of the body. Push the remaining organs to one 
side to see the nerves which supply them. The 
principal part of the sympathetic system consists 
of a row of nerves and ganglia lying on each side 
of the ventral median line of the spinal column. 
From the ganglia and nerves arise branches which 
run to the lungs, heart, principal blood-vessels, 
stomach, intestine, liver, kidneys, genital glands, 
etc. ; to the spinal and cranial nerves ; and be- 
tween the various parts of the sympathetic sys- 
tem. 

How do the sympathetic compare in size with 
the spinal nerves? How many sympathetic gan- 
glia do you find? What noticeable differences 
between these and the spinal ganglia can you 
detect ? 
Make a diagram of the sympathetic nervous system. 

c. The cranial nerves. 

To see these well, two specimens should be 
prepared, one to show a ventral view of the in- 
side of the skull, the other to show the ventral 
surface of the brain. The second may be pre- 
pared by removing one half of the floor of the 
mouth, the mucous membrane of the roof of the 
mouth, and the floor of the cranium and of the 
auditory capsules. Especial care must be exer- 
cised in order not to tear away the nerves from 
the parts to which they are connected. 



254 THE BIOLOGY OF THE ANIMAL 

The cranial nerves are numbered in the order 
of their origin from the anterior towards the pos- 
terior part of the brain : 

1. The first, or olfactory nerve, runs from the 
olfactory lobe to the membrane lining the 
nasal cavity. 

2. The second, or optic nerve, arises below the 
optic lobe, and passes through the optic chiasma 
to the eye on the opposite side. 

3. The third, or motor oculi, originates on the 
ventral surface of the brain near the pituitary 
body, and supplies some of the eye muscles. 

4. The fourth, or pathetic, arises on the dorsal 
surface of the brain in front of the cerebellum, 
leaves the cranium in front of the optic nerve, 
and runs to one of the eye muscles. 

5. The fifth, or trigeminal, runs forward from 
the anterior part of the medulla to leave the 
cranium immediately in front of the auditory 
capsule. Just within the place of exit look for 
the Gasserian ganglion. What is its exact 
position ? Compare it with the spinal and with 
the sympathetic ganglia. On the outer side 
of the ganglion the nerve divides into two 
branches : the first or ophthalmic nerve runs 
to the skin of the front part of the head and 
to the nasal cavity ; the second or maxillo- 
mandibularis divides into two branches, the 
maxillary nerve, which runs to the skin of 
the upper jaw and to the lower eyelid, and the 
mandibular nerve, which supplies parts of 
the lower jaw. 

6. The sixth, or abducens, originates near the 
median ventral line of the medulla, behind the 



FROG 255 

pituitary body, runs very near the Gasserian 
ganglion, and supplies some of the eye mus- 
cles. 

7. The seventh, or facial, arises immediately be- 
hind the fifth, runs forward to the Gasserian 
ganglion, and after leaving the cranium di- 
vides into two principal branches, one of which, 
the palatine nerve, supplies the roof of the 
mouth, while the other or hyomandibular 
nerve sends branches to the mandible, hyoid 
bone, and ear. 

8. The eighth, or auditory nerve, arises close 
to the seventh and passes to the internal ear. 

9. The ninth, or glossopharyngeal nerve, 
originates immediately behind the auditory 
nerve. Of its two main branches, one unites 
with the facial nerve and the other runs to 
the tongue and pharynx and the neighboring 
muscles. 

10. The tenth, the pneumogastric or vagus 
nerve, arises with the ninth and sends branch- 
es to the larynx, the lungs, the heart, and the 
stomach. Look for a ganglion on this nerve. 

Compare the cranial w r ith the spinal nerves, 
noting any resemblances and differences that 
you may discover. Do the cranial nerves origi- 
nate from anterior and posterior roots? To 
what region of body are these nerves mainly 
confined ? 
Make diagrams showing the origin and course of the 
cranial nerves. 

Let the student compare the nervous system of a 
frog with that of man as illustrated by a manikin or 
chart. 



256 THE BIOLOGY OF THE ANIMAL 

H. — The Eye and the Ear. 

a. The eye. — Examine the eye of a living frog, 
and make out the transparent outer portion or 
cornea, below which lies a pigmented ring, the 
iris, in the centre of which is a black opening, 
the pupil. What is the color of the iris ? How 
much of the exposed portion of the eyeball does 
it form ? What is the shape of the pupil ? Diam- 
eter ? Watch the eye carefully to see if the pupil 
changes in size. Kill the frog with chloroform, 
and remove the eyes by cutting the eyelids and 
muscles. Note how the lids are connected to the 
eyeball by means of the conjunctiva. Examine 
again the shape of the eye, and find the point of 
entrance of the optic nerve. Notice the white 
sclerotic membrane which forms the outer 
coat of the eye. Place the eyes in a watch-glass 
of water, and with sharp scissors divide one by 
a cut passing through the centre of the pupil and 
slightly to one side of the optic nerve ; the other 
by an incision at right angles to the line passing 
through the pupil and the nerve. With a lens 
study the sections first made and notice the black 
choroid membrane, which lines- the cavity or 
vitreous chamber, in which lies the vitreous 
humor. What is the relation of this membrane 
to the sclerotic ? To the iris ? What is the ap- 
pearance of the vitreous humor? Kemove it and 
examine its shape. Anterior to the vitreous hu- 
mor find the crystalline lens. What is its 
shape? Size as compared with the vitreous hu- 
mor? In front of the lens is the anterior 
chamber of the eye containing the aqueous 
humor. Examine the sections of the other eye, 



FROG 257 

and in that section which contains the outer half 
study the pupil. Why is the pupil black? From 
the inner section remove the vitreous humor, 
and back of it find a delicate membrane, the 
retina, covering the choroid. Look also for the 
point of entrance of the optic nerve, the blind 
spot. 
Make a drawing showing the eye in ant ero -posterior 

section ; another to show the layers of membrane in the 

posterior half of the eye. 

h. The ear. — The parts of the internal ear may best 
be dissected in preserved specimens which have 
been macerated in a mixture of sixty per cent, 
alcohol, to which a few drops of nitric acid have 
been added. Leave the specimen in the mixture 
until the muscles and bones assume a translucent 
appearance, then, with forceps, pick away the 
skin and muscles surrounding the auditory cap- 
sule, tear off the top of the latter, which now has 
the appearance and consistence of cartilage, and 
within will be found the membranous laby- 
rinth, which appears as a small white nodule, to 
which are attached grayish pigmented parts. 
Float the labyrinth into water in a watch-glass 
and examine it with a lens. The white portion, 
or vestibule, consists of two parts separated 
by a constriction, the lower part being the sac- 
culus and the upper the utriculus. From the 
upper arise the three semicircular canals, 
each of which bears at its base an enlargement, 
the ampulla. Endeavor to trace the connec- 
tions of the auditory nerve. 

Make a drawing showing the relation of these parts. 
17 



258 THE BIOLOGY OF THE ANIMAL 

Microscopic Anatomy. 

From the freshly killed frog and in the man- 
ner described the student will make and study 
preparations of the various parts named hereafter. 
These are such as may readily be made on a glass 
slide without elaborate manipulation. As only a 
few structures can be studied in this way, he 
should also have for examination a set of perma- 
nent preparations of various organs which have 
been hardened, stained, sectioned on a microtome, 
and mounted in Canada balsam. This material 
will be provided by the instructor, as the student 
has not yet had sufficient training in histological 
technique to enable him to prepare satisfactory 
specimens. Before staining a preparation always 
examine it in the fresh state in a drop of water 
or of normal salt solution. Make drawings and 
full notes of every specimen studied. 

a. The skin. 

Eemove pieces of skin from the various places 
on the dorsal and ventral surfaces of the body 
and from the limbs, mount in a drop of water, 
and look for the pigment cells and the open- 
ings of the cutaneous glands. 

o. The blood. — See page 23. 

c. Connective tissue. 

1. Fibrous tissue. — Tease a bit of the tendo 
Achillis in water. Note the arrangement and 
structure of the white, non - elastic fibres. 
Do they branch ? Apply a drop of dilute acetic 
acid. Look in this tendon and in those from 
other parts of the body for yellow, elastic 



FK0G 259 

fibres. Compare with the white. Look also 
for connective-tissue corpuscles. 
2. Areolar tissue. — Without stretching it, lay in 
a drop of water on a slide a portion of the thin, 
web-like tissue which connects many of the ad- 
jacent muscles, or, in places, attaches the skin 
to the underlying parts. What kinds of con- 
nective tissue can you find? Stain with ma- 
genta. Examine another specimen which has 
been treated with a one-half per cent, solution 
of silver nitrate for three to five minutes, then 
washed with distilled water and left exposed to 
the sun until brown. 

d. Hyaline cartilage. 

Dissect out the xiphisternum, remove its cov- 
ering membrane, the perichondrium, cut off a 
piece of the cartilage, and mount in a drop of 
salt solution. Note the arrangement of the car- 
tilage corpuscles embedded singly or in groups 
in the matrix. Look for nuclei, particularly 
such as show by their elongation, etc., that they 
are in the process of division. Wash the speci- 
men in water, stain with an aqueous solution of 
hematoxylin, and examine in glycerine. 

e. Adipose tissue. 

Cut off a portion of a fat body, tease it in a 
drop of salt solution, and study the structure of 
the tissue, which consists mainly of connective 
tissue and fat cells. Treat with chloroform. 

f. Muscidar tissue. 

1. XJnstriated muscle. — Remove a portion of the 
outer layer of the intestine and tease it in a drop 
of salt solution. Look for long, spindle-shape 



260 THE BIOLOGY OF THE ANIMAL 

cells. Apply acetic acid. Treat another prepa- 
ration with an aqueous solution of hematoxylin. 
2. Striated muscle. — Eemove a portion of the 
gastrocnemius and examine as above. Notice 
that the muscle consists of fibres. In the latter 
look for the striations, the nuclei, and the 
membrane or sarcolemma. Treat one prepa- 
ration with acetic acid, another with magenta. 

g. Nervous tissue. 

1. Nerve fibres. — Eemove a piece of the sciatic or 

other large nerve and carefully tease it in a drop 
of salt solution. JSTote the medullated nerve 
fibres held together by a membrane, the peri- 
neurium. Examine a single fibre and endeav- 
or to make out the surrounding membrane, 
called the primitive sheath or sheath of 
Schwann. Within this is the medullary 
sheath. The former is best seen in fibres 
which have been torn. In such fibres look also 
for the axis cylinder, projecting beyond the 
medullary sheath. Treat a preparation with 
chloroform, which will partially dissolve the 
fatty substance forming the medullary sheath, 
and thus make the primitive sheath and the 
axis cylinder more plainly apparent. 

2. Nerve cells. — Eemove a spinal ganglion and 

tease it in eosin. Examine the preparation for 
large spherical cells, each with a conspicuous 
nucleus. Examine in the same manner the 
cells from one of the sympathetic ganglia. 

h. The liver. 

Cut off a small piece of a fresh liver, tease 
in a drop of salt solution, and look for the hepatic 



FROG- 261 

cells. Treat the preparation with acetic acid. 
Treat another preparation with iodine ; the deep 
red color assumed by the contents of certain cells 
indicates the presence of glycogen. 
i. The testis. 

In a drop of water finely divide a portion of 
the testis of a recently killed frog, and look for 
actively moving spermatozoa. Apply magenta. 
To another preparation apply dilute iodine. 

PHYSIOLOGY 

A. Locomotion. 

Does the frog ever walk ? Eun ? Can it walk 
backward? Leap backward? Walk sidewise? 
Swim backward ? In swimming, what use is made 
of the fore limbs ? Can it float ? 

B. Nutrition. 

a. Feeding. — Place a frog in a low glass jar, beaker, 
or tumbler, along with a living fly. Watch the 
frog, to see how it catches the fly, noticing par- 
ticularly the action of the tongue. If it be other- 
wise impossible to get the fly within reach of the 
frog, kill the former by pinching its head, run a 
fine thread through its body by means of a needle, 
then lower the fly, dangling at the end of the 
thread, into the jar. If flies cannot be obtained, 
use a small piece of fresh meat. Can you give 
any reasons for the structural arrangement of the 
frog's tongue ? 

h. Breathing. — Watch the nostrils of a frog. Can you 
detect any motions ? Watch the throat and the 
sides of the abdomen. Do they move ? If so, do 
they move at the same time? While holding 
your hands on your sides, draw in a breath. Do 



262 THE BIOLOGY OF THE ANIMAL 

your ribs move ? Can you inspire deeply without 
moving the ribs ? Has the frog ribs, or anything 
corresponding to them? If so, are these parts 
movable ? Can they assist in inspiration ? Does 
the frog breathe as you do? Why can a frog 
stay under water for several days without coming 
to the surface to breathe? Why do frogs die 
when their skin becomes dry ? 

c. Circulation. 

1. The beat of the heart. — Chloroform a frog and ex- 

pose its heart. Note the beat of the heart, con- 
sisting of a contraction or systole, followed 
by an expansion or diastole. How rapid are 
the pulsations ? How do the ventricle and the 
auricles behave ? Do any of the parts change 
color during the beat ? Shape ? Size ? With 
the finger lightly touch the various parts of the 
heart while it is beating, and note the varia- 
tions in tension of the walls. Remove a heart 
from the body by cutting the blood-vessels, and 
immerse it in a salt solution in a watch-glass. 
Does the heart still beat, though it contain no 
blood? If so, how long does its activity last? 

2. The circulation through the web. — Provide a piece 

of thin board — e. g., such as is used for the backs 
of pictures — about four or five inches long and 
two or three inches wide. In the middle of one 
end bore a hole or cut a notch, over which the 
web of the frog's foot may be stretched. Ren- 
der the frog insensible with chloroform, but do 
not kill it. Lay it on the board, ventral side 
downward, and fasten it with a tape passed 
firmly, but not tightly, around its body a few 



FKOG- 263 

times. Make a slip noose in the ends of three 
or four threads, tighten the nooses around the 
tips of the toes, and by fastening the threads at 
different points on the board, lightly spread the 
web over the hole. Keep the frog under the 
influence of chloroform, and keep its body moist 
by spreading over it a damp cloth or a layer of 
wet, absorbent cotton. Examine the web with 
a low power, noting the pigment cells and the 
blood-vessels. Put a drop of water on a part of 
the web, lay on it a bit of cover-glass which 
will fit between the toes, and examine the prep- 
aration with a high power. Study the flow of 
blood in the various vessels, and note the be- 
havior of both red and colorless corpuscles. 

C. Development. 

In the early spring, when the ice is leaving the 
ponds and streams, frogs' and toads' eggs may be 
found in abundance as slimy masses fastened to 
reeds and water-plants, or floating on the surface. 
Each mass consists of a number of small, black, 
berry-like bodies, each of which is embedded in 
a gelatinous matrix. One of these masses should 
be transferred to the laboratory, placed in a large 
jar of water, which should frequently be changed, 
and the eggs examined from day to day. The va- 
rious stages of segmentation may be studied, and 
the development of the tadpoles watched. As 
soon as the latter appear, they must be provided 
with a supply of water-plants to which they may 
attach themselves. 

For comparison with the frog make a general 
examination of a fish or a bird. 



Paet III 
THE BIOLOGY OF THE PLANT 



THE BIOLOGY OF THE PLANT 



Green Felt ( Vaucheria Sp.) 

Material. — Various species of Vaucheria grow as a 
coarse, dark-green, felted mat on the rocks and timbers 
in streams, and on the surface of the earth in the beds 
and flower-pots in greenhouses. In the latter situation 
they may be had all the year round. The terrestrial 
species may be kept growing indefinitely by transfer- 
ring to the laboratory some of the earth with the plant 
and covering it with a bell-jar. The aquatic species 
should be put into a low aquarium with plenty of mud 
and flat stones, and be kept covered with water three or 
four inches deep. In both situations the plant needs 
plenty of sunlight. Alcoholic material may be prepared 
according to the directions given for Spirogyra. 

Iodine, carmine, Schulze's solution, two per cent, salt 
solution, saucer, fine forceps, pipette, hand -lens, etc., 
will be used in the examination. 

Method of Examination. — The structure of this plant 
necessitates the most careful handling, in order that 
good specimens may be obtained. A small portion of 
the felted mass should be placed in a small dish of water, 
and gently shaken until some of the plants separate 
from the mass and float in the water. With a pipette 



268 THE BIOLOGY OF THE PLANT 

transfer two or three of these to a slide, and cover with 
a glass supported by a piece of hair or a scrap of paper. 

MOEPHOLOGY 

A. — Vegetative Condition. 

I. Naked-eye characters. — Examine the plant as it 

grows in the water or on the surface of the soil. 
Compare it with Spirogyra in mode of growth, 
color, length of filament, etc. Does it have or- 
gans of attachment, as roots ? Does it have the 
slimy feel of Spirogyral Do you ever find it 
forming a frothy scum on the surface of the 
water? Why? Do the tips of the filaments 
ever project above the surface of the water? 
Why ? Do these tips point towards the sun or 
away from it ? Do you find any difference in 
the direction of the tips of filaments exposed to 
strong sunlight and those exposed to less intense 
light ? Why is it called " Green Felt " ? 

II. Microscopic characters. — Examine first with a low, 

then with a high power. 

a. Shape. — What is the shape ? Is the filament sim- 
ple or branched ? If branched, do the branches 
originate at any particular points ? What rela- 
tion of position exists among the branches ? Does 
it have roots? What is the shape of the end of 
the filament ? In what respects does this plant 
differ in shape from Spirogyra ? 

h. Size. — How long is a filament ? Is its diameter 
greater or less than that of the species of Spiro- 
gyra examined ? Does it have the same diameter 
throughout its entire length ? 



GREEN FELT 269 

c. Color. — "What is it ? Is it evenly or unevenly dis- 
tributed? To what is it due? Is it darker or 
lighter than Spirogyra ? "Why ? 

d. Structure. — Is the filament composed of cells? 
How many ? How are the cells situated with 
regard to one another? Compare with Spiro- 
gyra. Can. you distinguish cell-wall, vacuole, nu- 
cleus, starch grains, pyrenoids, etc. ? Do you 
find chromatophores, as chlorophyll bodies ? 
What is their shape ? Arrangement ? How do 
they compare in size, color, arrangement, shape, 
etc., with those of Spirogyral Look for chloro- 
phyll bodies in the process of division. Plasmo- 
lyze the filament with two per cent, solution of 
salt or sugar in water, and examine the primor- 
dial utricle. Does the cell-wall show any pro- 
tuberances, stratification, or openings ? What is 
its color? Look for spherical, glistening oil- 
drops in old filaments. Is the surface of the fila- 
ment of this plant as clean and free from other 
organisms as is Spirogyra ? Does Vaucheria have 
the characteristic mucous coating of Spirogyra ? 
What is there about Vaucheria which enables it 
to form a " felt " ? Why cannot Spirogyra do the 
same? 

Make drawings illustrating all of the structures ex- 
amined. 

B. — JReproductive Condition. 

Can you identify the reproductive stage with- 
out making a microscopic examination ? How ? 
Find some plants bearing sexual organs, which 
may be distinguished as short outgrowths from 
the side of the filament. 



270 THE BIOLOGY OF THE PLANT 

I. The sexual reproductive organs, or gametangia. 

On mature specimens look for the curved an- 
theridia and the oval obgonia. On what part 
of the plant are they found? Does the same 
plant bear both organs ? How many of each do 
you find on one filament ? How are they situated 
with regard to each other ? What differences do 
you find in shape, size, and color ? 

a. The antheridium or male organ. — What is its 
shape ? Compare its diameter with that of the 
filament. Note the pedicel or stalk — its shape 
and structure. What does it contain ? How is it 
connected to the filament ? Does its cavity com- 
municate with that of the filament ? With that 
of the antheridium proper ? Look for anthero- 
zoids or sperm-cells in the antheridium. What 
is their shape ? Color ? Arrangement in the an- 
theridium ? Examine a number of specimens to 
find antheridia in various stages of development. 
If any are found, make sketches of them. Look 
for empty antheridia. In what respects do they 
differ from the other ? Look for antheridia from 
which the antherozoids are escaping, and study 
the details of the process — how the antherozoids 
are set free, their motions, and general behavior 
after leaving the antheridium. If antherozoids 
are found, apply iodine in order to see their cilia. 
How many have they ? 

b. The oogonium or female organ. — Compare 
with the antheridium in shape, size, color, and 
mode of attachment to the filament. Is its cavity 
continuous with that of the filament? Does it 
have a pedicel ? Endeavor to trace the develop- 



GEEEN FELT 271 

ment of the oogonium by examining specimens 
which show it in various stages of growth. Of 
how many cells is it composed ? Compare with 
antheridium. Try to see the manner in which a 
mature oogonium opens by the top becoming 
gelatinous. Endeavor to see the antherozoids 
enter. Examine oogonia which have been fer- 
tilized. What changes have taken place in the 
color, shape, and arrangement of the contained 
protoplasm, or oosphere, and in the cell- wall? Is 
the oogonium a motile organ ? Is the fertilized 
oogonium in actual contact with the antheridium? 
Compare with Spirogyra. "What is the structure 
of the ripe oosphere, now called oospore? Are 
there any organs of motion on it ? Compare with 
the zygospore of Spirogyra. 
Draw a filament showing the facts learned about the 
reproductive organs of Vaucheria. 

II. The asexual reproductive todies. 

a. The zoogonidia or zoospores. — Place some vig- 
orous plants in water in a dark place overnight, 
then examine for zoogonidia early the next morn- 
ing, or keep the plants in the dark until ready to 
make the examination. Put some of the plants 
into a porcelain dish, and with a hand -lens look 
for filaments having swollen ends. These fila- 
ments are ready to form zoogonidia. Mount 
some of these filaments without a cover -glass. 
How much of the filament is occupied by the zoo- 
gonidium ? What is the shape of a zoogonidium ? 
Color ? How does it move ? What are its organs 
of motion? Where are they situated? What ap- 
propriateness about the name "zoogonidium"? 



272 THE BIOLOGY OF THE PLANT 

"Zoospore"? Stain with iodine, and look for 
nuclei. Treat a moving zoogonidium with two 
per cent, salt solution to plasmolyze it. Do you 
find a cell- wall apparent ? Treat in like manner 
a zoogonidium which has come to rest, and com- 
pare it with the first. 

Try to find filaments in which the formation of 
zoogonidia is going oh, and study the process. Is 
the zoogonidium formed by the union of sexual 
cells ? Is the protoplasm of the zoogonidium sep- 
arated from that of the cavity of the filament ? 
Where a mature zoogonidium is found, watch to 
see it escape from the filament. 

Study a zoogonidium which has come to rest, in 
order to see the process of germination. 

General Questions. — As regards structure, is Vaucheria 
more or less complicated than Spirogyral As regards 
reproduction, which is the more complicated ? What is 
the advantage in having zoogonidia ? 

What means of dispersal has Vaucheria \ Of protec- 
tion \ 

Draw a filament, showing the stages in the formation 
of a zoogonidium, a mature zoogonidium, and the ger- 
mination of the same. 



Stone wort (Char a Sp.) 

Material. — Species of Chora are to be found growing 
in tangled masses in the bottoms of ponds, ditches, and 
slow-flowing streams. A handful of the plants may be 
pulled out of the mud and placed in a deep aquarium 
jar having a layer of mud two or three inches deep in 
the bottom. The plants should have an abundance of 
water. Small snails feed upon them, and there will 
probably be a good many of these attached to the plants. 
All bat a few of these snails should be removed, other- 
wise they will injure and possibly destroy the plants 
by eating the buds and young branches. The fruiting 
stages are to be found during the late summer and 
fall. Aquarium specimens may continue to fruit until 
late in the winter. It is well,, however, to preserve the 
fruiting stages when found, rather than run the risk of 
not having them fresh when wanted. Plants may be 
preserved in alcohol, passing them through the various 
grades from fifty per cent, to ninety-five per cent, as 
usual ; or, better, place them for a clay in one per cent, 
solution of chromic acid, wash for ten to fifteen minutes 
in running water, then place successively in fifty per 
cent., seventy per cent., eighty per cent., and ninety-five 
per cent, alcohol for about twelve hours each. 

The student will need clissecting-needles, hand-lens, 
compound microscope, glass or porcelain bowl, fine for- 
ceps, dilute hydrochloric acid, pith, razor, pipette, watch- 
glass, a pair of dividers, iodine, carmine, magenta, fifty 
18 



274 THE BIOLOGY OF THE PLANT 

per cent, glycerine, metric scale, scalpel, and chromic 
acid. 

Method of Examination. — First examine the plants as 
they grow in a mass in the pond or aquarium, then care- 
fully remove a plant from the tangle without breaking 
any parts, and study its gross anatomy by floating it in 
a dish of water, if the plant be living, or in fifty per 
cent, alcohol if the specimen has been preserved. 



MORPHOLOGY 

Naked-eye Characters. 

a. General appearance. — Note the plant as it grows 

in the pond or aquarium. What is the color of 
the mass? Is the mass dense or loose? Lift a 
handful. Is it heavy or light ? How does the 
plant feel to the touch? Compare with Spiro- 
gyra and Vaucheria in this respect. Can you sug- 
gest any reasons why the plant should be named 
" Stonewort " ? Does it grow up to the surface of 
the water ? If so, does it rise and fall with the 
water, or are the lower portions strong enough 
to support the upper portions of the plant? Or,' 
does Char a, like various twining plants — e. g., 
the morning-glory — depend upon other plants 
or upon some artificial support to hold it up? 
What is there about the aquatic habits of this 
plant which will explain its mode of growth? 
Can you detect any peculiar odor about Chara ? 
If so, is it the odor of the water or of the plant ? 

b. Shape. — Carefully separate from the mass a single 

plant and float it in a dish of water. What is 
its general shape? Can you plainly distinguish a 



ST0NEW0RT 275 

lower, or root end, from an upper, or stem end ? 
How? Do you ever find roots except at one end 
of the plant ; i. <?., does the plant ever take root at 
the joints ? 

c. Size. — Select four or five plants and measure their 

length. Do you get any very great variations in 
length ? If so, how do you explain them ? Any 
variations in diameter ? How much of the length 
do you consider to be " root end " ? How do 
length and diameter compare ? 

d. Color. — What is the general color of a single plant ? 

Does the color vary in different portions of the 
plant body? If so, where is the color deepest? 
Where lightest? How do you explain these 
facts? 

e. Structure. — Does the main stem bear appendages 

or branches? If so, do they originate at any 
particular points ? How do they compare in gen- 
eral appearance with the main stem ? Do the 
branches in their turn branch also? Note the 
circles or whorls of leaves on the stem. How 
do you distinguish leaves from branches ? Where 
are the whorls most numerous ? Do they occur 
at definite points? Do you find them on the 
branches? Are the leaves regularly arranged 
in the whorls ? Do you find green and orange 
colored bodies, reproductive organs, on the 
leaves ? Do you find these bodies elsewhere than 
on the leaves? Are the leaves subdivided into 
leaflets ? If so, how do you distinguish the latter ? 
Note that the main stem consists of a series of 
segments or internodes which meet at joints or 
nodes. Do you find that the appendages like- 



276 THE BIOLOGY OF THE PLANT 

wise consist of nodes and internodes % What 
relation exists between the appendages and the 
nodes ? What variations in the length of the in- 
ternodes do you find ? Put a piece of the lower 
portion of a plant into dilute hydrochloric acid. 
What result ? Try the tip end. Do you get the 
same result? Compare with the similar experi- 
ments on the exoskeleton of the lobster and on 
the mussel shell. 
Make a drawing, showing the last six internodes and 
appendages. 

Microscopic Structure. 

a. The stem. — With the hand-lens examine one of 
the upper internodes in water. Notice the elon- 
gated cells running in a spiral from the base to 
the apex of the node. How many turns does the 
spiral make ? Does the internode have any out- 
growths ? Lay the same specimen on a slide and 
examine under the low power, using no cover- 
glass. Can you now trace the course of the spiral 
cells ? Is each one continuous from one node to 
the next ? If not, do you find that each spiral is 
made up of the same or of different kinds of 
cells ? If the latter, how many kinds do you 
find, how do they differ from one another, and 
how are the various kinds arranged? Examine 
the lower portion of the stem and compare with 
the upper. 
Draw two or three segments of the stem. 

Hold a piece of a fresh or preserved stem be- 
tween two pieces of pith, and with a sharp razor 
cut thin transverse and longitudinal sections 
through nodes and internodes. With a pipette 



ST0NEW0RT 277 

wash the sections into a watch-glass, place some 
of those made through the internode upon a slide 
with a drop of water, put on the cover-glass, and 
examine with the low power. Note that the sec- 
tion consists of a central or internodal cell sur- 
rounded by the cortical cells. How does the 
internodal compare with the cortical cells in size ? 
In shape? In contents? Is the central cell di- 
vided? Does it communicate with the cortical 
cells ? Does it extend through the nodes, or is 
there a single internodal cell for each internode ? 
How many cortical cells are there ? Do they have 
the usual contents of the cells of green plants, i. e., 
protoplasm or primordial utricle, vacuole, starch 
grains, chlorophyll bodies, etc. ? Note the nodal 
cells and compare them with the others. Com- 
pare several specimens to see if you can find any 
variations regarding the topics just studied. 
Make drawings illustrating your results. 

b. The leaves. — With the scalpel cut loose from the 
stem two' or three vigorous leaves, mount them in 
a drop of water, and examine under the low power. 
What is the shape of the leaf ? Does it, like the 
main stem, consist of segments ? If so, how many 
segments do you find in each leaf? Examine 
several leaves to see if the number is constant. 
Do you find nodal, internodal, and cortical cells ? 
Are the latter arranged in spirals? Do these 
cortical cells differ in any important particular, 
as shape, arrangement, contents, etc., from those 
on the stem? Are cortical cells present on all of 
the internodes of the leaf? If not, which inter- 
nodes lack them ? Are these uncorticated inter- 



278 THE BIOLOGY OF THE PLANT 

nodal cells the same in position and number on 
all the leaves? What is the shape of the end 
cell of the leaf? Notice the leaflets. On what 
part of the leaf do you find them ? Do they dif- 
fer in any important details from the leaves? 
Are the leaflets arranged in whorls ? Are all the 
leaflets at one node equally well developed ? Do 
you find any relation existing between the leaves 
and the point of origin of the branches? 

Put on the high power and examine the cells 
of the same leaf. Do you find that they have 
the usual cell contents? Note the chlorophyll 
grains. What is their shape? Size? Position 
in the cell ? Do you find any part of the cell- 
wall which is not covered by the chlorophyll 
bodies? Are the chlorophyll bodies in contact 
with one another ? Do you find any of them di- 
viding? Are they stationary or do they move? 
What plant have you examined whose chloro- 
phyll bodies most closely resemble these ? Notice 
the thickness of the cell-wall. Notice the proto- 
plasm moving in the end cells of the leaf. (This 
topic will be studied later under " Physiology.") 
Make drawings of the structures of the leaf. 

c. The reproductive organs. 
1. The antheridia. — Select two or three leaves 
upon which may be seen, with or without a hand- 
lens, small, orange-colored bodies, the mature an- 
theridia. On which leaves are the antheridia 
borne in the largest numbers? Examine with a 
low power. On what part of the leaf do you find 
them ? What is their relation to the nodes ? To 
the leaflets? Are the antheridia situated with 



STONE WOET 279 

reference to any particular leaflets ? If so, which ? 
Why are they so situated % What is the shape of 
an antheridiuni % To what portion is the color 
confined ? How is the surface marked ? By com- 
paring a number of antheridia which lie in differ- 
ent positions try to make out that the surface of 
each is divided into eight areas, the shields. The 
centre of each shield is indicated by a circular 
cell. From this radiate oblong cells, which unite 
in a dentate manner with similar cells forming 
parts of neighboring shields. The four shields 
covering the outer end of the antheridium are 
somewhat square in outline ; the other four, at 
the base of the antheridium, are nearly triangu- 
lar. With a dissecting-needle tap gently on the 
surface of the cover-glass, and try to separate an 
antheridium from its point of attachment. Can 
you detect a stalk ? Carefully press upon the 
cover-glass until the antheridium breaks. Exam- 
ine with the high power one of the shields. To 
what is the color of the antheridium due % No- 
tice projecting into the centre of the sphere from 
the central cell, seen on the outside, a single club- 
shaped cell, the manubrium. If the antherid- 
ium is not too deeply colored, these manubria 
may frequently be seen in their natural position 
without crushing the antheridium. On the end 
of the manubrium find a rounded cell, the capit- 
ulum, to which are attached several smaller 
cells, the secondary capitula. From these 
grow a number of elongated filaments. What is 
the shape of these filaments ? Color ? What is 
their structure ? Estimate the number of cells in 
one filament. Try to find in each cell a spiral 



280 THE BIOLOGY OF THE PLANT 

spermatozoid. If the antheridium be quite ma- 
ture, some of the spermatozoids may be seen 
swimming about in the water. If so, examine 
them carefully. What is their shape ? Do they 
have the same diameter at each end? At their 
anterior end look for two long flagella. If the 
structure of the spermatozoid is not plain, apply 
dilute iodine. How do the spermatozoids move ? 
For how long is their motion kept up ? Look for 
antheridia in different stages of development. 
Study and draw the stages found. 
Make drawings showing : (1) the antheridium as seen 
from the outside ; (2) a shield seen from without ; (3) a 
shield with manubrium, etc. ; (4) a spermatozoid. 

2. The oogonia. — Compare these as regards posi- 
tion, shape, size, color, etc., with the antheridia. 
Do you find any constant relation existing be- 
tween the position of the antheridia and that of 
the oogonia ? Is the oogonium borne upon a stalk ? 
Note its outer covering of spirally twisted cells. 
Do these run as single cells from the base to the 
apex of the oogonium ? How many are there ? 
Note the crown, consisting of small cells. What 
is their number ? What is their position with re- 
gard to the spiral cells ? Note the central cell or 
oosphere of the oogonium. How does it com- 
pare in size with the other cells? What does it 
contain ? Certain points in the structure of the 
oogonium may be found to be more easily seen 
in specimens preserved in chromic acid and exam- 
ined in glycerine. 
Draw an oogonium, showing its entire structure. 

Examine a number of specimens for oogonia in 



ST0NEW0RT 281 

various stages of growth. Do you find any, es- 
pecially the very young oogonia, in which the 
outer cells have not yet taken the spiral form? 
Do you also find some in which the spiral cells 
have become dark-colored and hard, the ripened 
oospores ? 
Draw all of the stages found. 

d. The terminal bud. — With scissors cut off the upper 

portions of several plants, put them into one per 
cent, chromic acid for a day, then remove one of 
the terminal buds to a drop of glycerine on a 
slide; with dissecting-needles pick away all of the 
lower parts of the bud, remove these, and put on 
the cover-glass. While examining the bud under 
the low power gently tap and press upon the 
cover so as to push away all of the undeveloped 
leaves which cover the apex of the stem. How 
are the leaves arranged in the terminal bud ? Can 
you trace nodes and internodes in the bud ? At 
the very tip of the main axis find the apical cell. 
What is its shape ? Does it have the usual cell 
contents ? How many nuclei does the cell con- 
tain % Do you find a single cell, the segmental 
cell, just below the apical cell ? By tracing back 
from the apex endeavor to see how the nodal and 
internodal cells are formed, and how the nodal 
cells eventually give rise to the cortex and to the 
leaves. 
Make drawings to illustrate your observations. 

e. The rhizoids. — Examine the nodes and the lower 

end of the main stem of living plants for the floc- 
culent clusters of root-like appendages, the rhi- 
zoids. Do you find them on the internodes % On 



282 THE BIOLOGY OF THE PLANT 

the leaves ? At all of the nodes ? Are all the rhi- 
zoids surrounded by masses of mud? Examine 
under the low power. What is the arrangement 
of the rhizoids borne at one point on the stem ? 
Are they arranged in whorls? Do they origi- 
nate from particular cells? If so, from which 
cells? Do two or more rhizoids originate from 
the same cell ? Put on the high power and study 
a single rhizoid. What is its shape ? Does it vary 
in diameter ? Is it segmented ? Does it have a 
layer of cortical cells ? Of how many cells does 
it consist ? What are its contents ? Note the cir- 
culation of the protoplasm, which will be studied 
later. 
Draw several rhizoids, showing their shape, structure, 

mode of attachment to the stem, contents, etc. 

If specimens of Nitella can be obtained they should 

be compared with Chara. 

PHYSIOLOGY 

a. Growth. — Put a single vigorous plant into a dish of 
water. With a pair of dividers accurately meas- 
ure each internode, beginning at the lower end of 
the plant, and record the measurements. What 
is the length of each internode and of the entire 
plant? Place the dish in a window where the 
plant may have plenty of sunlight. At the end of 
a week measure all of the internodes again and 
record the measurements. Do this for two or 
three weeks in succession. How much has the 
plant grown in length in this time? Is the in- 
crease due to the formation of new internodes or 
to the lengthening of those already formed at the 
beginning of the experiment or to both? If to 



STONE WORT 283 

the first, where have the new internodes formed ? 
Do you find that new internodes form oetween 
the others ? If growth is due to the lengthening 
of the internodes, which have lengthened the 
most ? Do you find that your results hold good 
for the branches as well as for the main stem? 
Does the diameter of the stem increase also ? 
ISTote the liberation of bubbles of oxygen from 
plants exposed to the sunlight. Compare with 
Spirogyra. 

o. Movements of protoplasm. — With a high power ex- 
amine the terminal cells of a leaf of Ohara, or, 
better, an entire internode of JVitella, and note 
the moving protoplasm. In what part of the cell 
is it seen ? What is the direction of the flow ? 
Examine several cells to see if this is uniform. Is 
the rate of flow the same in all cells ? Is it uni- 
form in all parts of the same cell ? Are the chlo- 
rophyll bodies carried along by the stream? Does 
the stream flow from one cell into another ? Can 
moving protoplasm be found in all of the cells of 
the same plant ? If not, in which cells is it found ? 
What is the color of the protoplasm? Note the 
granules carried along by the current. How long 
does it take a granule to make the circuit of the 
cell? 

Examine in like manner some of the rhizoids, 
and compare the moving protoplasm in them with 
that in the leaves. 

General Questions. — Is the plant so firmly attached by 
its roots to the mud in which it grows, and is the root- 
system so well developed, as to warrant thinking that 
Ohara absorbs a large part of its nourishment through 



2*4 THE BIOLOGY OF THE PLANT 

its roots? If not, how does the plant probably get it- 
nourishment i Is it like Spirogyra and Vcmcheria in this 
respect \ Of what use is the limy coating ? Do you find 
that, aside from the reproductive organs, there is any 
great variety of shape, size, structure, etc., exhibited by 
the cells of Chara' 1 . What structural resemblances do 
you find to exist between leaf and stem? What dif- 
ferences in their terminations ? 

Break the branches off a vigorous plant, put them in 
water, and watch them for several weeks. Do they con- 
tinue to live? If so, could Chara be propagated in this 
way, L e., without the formation of spores? 

Do you find any points of resemblance between Chara 
and Vaucherial 

Does the general plan upon which Chara is construct- 
ed, *. e., a segmented body with segmented appendages, 
remind you of any animal which you have studied ? 

What do you regard as the most striking feature of 
the cells of Chara ? 

Compare Polysiphonia, one of the red sea- weeds, with 
Chara. 



Rock weed (Fucus J5p.) 

Material. — Rockweed is to be found almost every- 
where along the coast, attached to the surface of rocks, 
timbers, shells, etc., or carried along by the currents or 
cast ashore. It can be sent on a several days' journey 
inland and arrive in good condition, if care be taken to 
pack it in a close wooden or tin box. On arrival it should 
be placed in real or artificial sea water, if a prolonged 
study is to be made. Otherwise, it may be kept in good 
condition if laid in a cold, clamp place. It should not, 
however, be moistened directly with fresh water. In 
many towns it is possible to get good material from res- 
taurant keepers and fish-dealers, who receive the rock- 
weed as packing around lobsters, crabs, etc. For the 
study of structure, alcoholic is better than fresh material. 
The plants may be put directly into alcohol, beginning 
with fifty per cent, and passing through the various 
grades, leaving the specimens from twelve hours to a day 
in each grade ; or, they may be placed for two to four 
hours in a mixture consisting of one part of a saturated 
solution of picric acid in sea water to four parts of sea 
water; then, after washing for about fifteen minutes 
in sea water to remove the excess of the acid, passed 
through the different grades of alcohol. 

Additional requisites consist of the compound micro- 
scope, hand-lens, fine forceps, scalpel, razor, watch-glass, 
pipette, glycerine, sulphuric acid, Schulze's solution, 
glacial acetic acid, and pith. 



286 THE BIOLOGY OF THE PLANT 

Method of Examination. — Laboratory specimens, if 
living, should be studied in sea water; if alcoholic, in 
fifty per cent, alcohol. Sections are most easily cut from 
the preserved specimens and must be examined in a mixt- 
ure of glycerine and fifty per cent, alcohol. Sections 
of fresh material should be studied in sea water or in 
a mixture of three parts of salt to one hundred parts of 
fresh water. Inland students may sometimes be fortu- 
nate enough to see the extrusion of the sexual cells, if 
plants gathered at high tide be sent them, accompanied 
by a supply of sea water. On receipt of the plants 
they should be divided into two sets. Place the first set 
in the sea water. Hang the second set in a cool place. 
Leave both sets for about six hours. During that time 
some of the hanging plants will probably have extruded 
their sexual cells, the male cells or antheridia being 
orange-yellow, the female cells or oogonia olive. Then 
hang up the plants which have been in water, and place 
the hanging plants in the water for about six hours. 
This may be repeated a great many times. 

MORPHOLOGY 

Naked-eye Characters. 

a. General appearance. — If possible study the plant 
as it grows, attached to the face of a rock or to 
the surface of a timber. Note its relation to the 
tide marks, its rise and fall with the tide, etc. 
Dig down into a mass of the plants left exposed 
by the fall of the tide, and note the differences 
between those plants which are on the surface 
and those deep down in the mass. Then examine 
an entire fresh or preserved specimen. "What is 
the general shape of the plant-body, or, as it is 



KOCKWEED 287 

called in this case, thallus ? What is the color of 
the thallus? Does the color vary in different 
places ? Does the plant apparently contain chlo- 
rophyll ? Place a plant in sixty per cent, alcohol 
for a few hours. What change in the color of the 
alcohol ? In the plant \ Is the plant of sufficiently 
firm structure to stand upright by itself? Can 
you distinguish an upper and a lower side on the 
thallus ? The plant consists of an attached por- 
tion or disk, from which proceeds the stem, the 
latter dividing into flattened branches. 

h. The disk. — Shape of the disk? In structure which 
does it resemble the more closely, the stem or the 
branches ? By what means is the disk attached ? 
Is it very firmly attached ? Is the plant attached 
by any other part than the disk? Do you ever 
find more than one stem growing from the same 
disk ? Is the disk merely an organ of attachment, 
or does its appearance warrant regarding it an or- 
gan of absorption, or root, as well ? 

c. The stem. — Where does the stem begin ? Is 

there any sharp distinction between disk and 
stem ? What is the shape of the stem ? Does it 
on its lower part bear any wing-like expansions ? 

d. The branches. — Trace the branches of the stem 

up into the expanded portions or branches of the 
thallus. Here they form the midribs of the flat 
branches. How do you distinguish the midrib 
from the other parts, wings, of the branch? 
What part of the branch does the midrib occupy? 
Does each branch have a midrib ? If so, does it 
extend to the end of the branch \ Note the 



288 THE BIOLOGY OF THE PLANT 

manner in which the midrib subdivides. Is it 
regular ? Are all of the branches flattened in the 
same plant ? Note at certain points on the thallus 
of some of your specimens smooth swellings, the 
vesicles. Whereabouts on the thallus are these 
most numerous ? Are they arranged in a definite 
manner with regard to one another ? With regard 
to the branching of the midrib ? Are they thick- 
enings of the midrib or of the wing? Pinch one 
of these swellings between the thumb and the fin- 
ger. Is the swelling hard or soft ? Can you easily 
break it by pinching ? With the razor cut one of 
the vesicles in two. What do you find inside it? 
What is the nature of its wall ? Being careful not 
to injure the vesicle, cut off a portion of the branch 
about an inch long, containing one or more vesi- 
cles, and throw the piece into salt water. Does 
the piece float or sink ? Try the same experiment 
with another portion of the branch free from ves- 
icles. What result ? What is the use of the ves- 
icles in a plant which grows attached to a solid 
substratum ? 

Examine the tips of some of the branches. Do 
you find them swollen and covered with tufted 
points, the conceptacles ? Do these conceptacles 
have a definite arrangement ? Do you find them 
elsewhere than on the tips of the branches ? Do 
they occur on the midribs ? On both sides of the 
branch? Pinch such a tip. Is it as firm and 
hard as the rest of the thallus? Examine some 
of the conceptacles with a hand-lens. What is 
the cause of the tufted appearance? Can you 
find in the centre of each tuft an opening, the 
ostiole, which leads into the cavity of the concep- 



R0CKWEED 289 

tacle? "With a scalpel cut open the swollen end 
of a branch. What is the appearance of the 
inside ? 

Sketch a plant and show all of the features ob- 
served. Examine the tips of branches which are 
not swollen. Do they likewise bear conceptacles ? 
Note that the extreme tip is indented. In the bot- 
tom of the depression lies the growing point. 
Put a piece of the thallus into fresh water. Does 
the piece gradually become slimy? Does it in- 
crease or decrease in size ? Does it go through 
these changes in salt water? Why must speci- 
mens be studied in salt water, or in alcohol, or in 
glycerine and alcohol? 

Microscopic Examination. 
a. The branch. — Hold a piece of a young branch of 
a preserved specimen between two pieces of pith, 
and with the razor cut both transverse and longi- 
tudinal sections, and examine in glycerine with 
the low power. What is the shape of the outline 
of the branch ? Notice the arrangement of cells 
in the section, certain cells forming a surface or 
cortical band, which shades off through a layer 
of parenchyma into a central mass or me- 
dulla. Do the former resemble the cortical cells 
of Chara in arrangement, shape, size, color, etc. ? 
Is the position of the midrib well defined ? Put 
on the high power and examine the same section. 
Study the cortical cells. How are they arranged ? 
How far towards the middle of the branch do they 
extend ? Are they sharply marked off from the 
underlying tissue ? What is their color ? Do you 
find the same color elsewhere in the section ? 
19 



290 THE BIOLOGY OF THE PLANT 

What is their shape ? Are there any marked 
variations in shape ? Do they differ much in size ? 
Does their wall vary much in thickness? If so, 
where is it thickest ? What do the cortical cells 
contain ? Do you find starch ? Are their con- 
tents more or less abundant than those of cells 
lying near the middle of the thallus ? If so, can 
you explain why ? Examine the layer of paren- 
chyma which lies between the cortical cells and 
the medulla. Is this layer sharply denned? 
What is the general shape of these cells ? Are 
they well filled with contents ? Is starch present ? 
Note that the walls of many of the parenchyma- 
tous cells are thickened and marked with circu- 
lar, oval, or irregular dots, the pits. Study the 
medulla. What is its color ? Notice how exceed- 
ingly thick the cell-walls appear. How do the 
cavities of the medullary cells compare in shape 
and size with those of the cortical and parenchy- 
matous cells ? What do the medullary cells con- 
tain ? Test for starch. Is it present ? Place a 
section in a drop of fresh water and watch the 
changes in the medulla. What happens? Do 
your observations on this section explain the 
changes seen when a portion of the thallus was 
placed in fresh water ? Apply a drop of strong 
sulphuric acid, which dissolves cellulose, to a sec- 
tion. What happens to the cells of the medulla ? 
To the cortical cells ? Do the walls of the corti- 
cal cells, particularly the outer walls, consist of 
cellulose? To another section apply a drop of 
Schulze's solution. What change in the walls 
of the medullary cells ? Do you find an inter- 
cellular substance which is not cellulose? 



R0CKWEED 291 

Does this experiment confirm the result obtained 
with sulphuric acid ? What effect has Schulze's 
solution on the outer wall of the cuticular cells ? 
Draw the section as seen under the low power, show- 
ing the shape of the branch and the position of the 
various tissues. Make another drawing of a portion of 
the section seen under the high power, and showing the 
structure, etc., of the various cells. Make longitudinal 
sections of the young branch and compare them with 
the transverse sections. Draw. 

Examine as above transverse and longitudinal sec- 
tions of the older branches and of the stem. 

b. The growing point. — Some of the longitudinal 
sections of the young branch made above prob- 
ably pass through the notch at the end of the 
branch. If not, make such sections, mount in a 
drop of a mixture of equal parts of glycerine and 
glacial acetic acid, and examine under the high 
power. What is the shape of the notch? Of 
the tips of the branch on each side of the notch ? 
Note that the notch contains a clear mucilagi- 
nous substance. Does this entirely fill the de- 
pression? Does it extend around on the tips of 
the branches ? If so, how far ? Of what use 
may it be ? Note the group of cells, the initial 
cells, at the bottom of the notch. How are they 
arranged? What is their relation to the sur- 
rounding cells ? Notice the large central eel], 
the initial or apical cell. What is its position 
with regard to the other initial cells? To the 
bottom of the notch ? What is its shape ? Size 
as compared with the neighboring cells? Can 
you make out the manner in which this cell di- 



292 THE BIOLOGY OF THE PLANT 

vides to form the surrounding tissues? Trace 
back into the older portions of the branch the 
rows of cells which have their origin from the 
initial cells. How do these tissue-cells change in 
shape and contents as they get older ? 

Draw your section. 

Make transverse sections across the young branch, 
cutting through the growing point as well as above 
and below it. 

Compare with the longitudinal section and draw. 

c. The vesicles. — Examine transverse and longitudi- 

nal sections of the walls of the vesicles. Do you 
find all of the tissues present ? Look for vesicles 
in various stages of development. Judging from 
their structure, how do you imagine the vesicles to 
be formed ? Draw the sections. 

d. The conceptacles. 

1. The sterile conceptacles. — With a hand-lens 
search among your sections for some which 
have passed through the conceptacles. Mount 
several of these sections in a drop of the mixt- 
ure of glycerine and acetic acid, examine with 
the low power, and find a section which has 
passed through the centre of a conceptacle. 
"What is the shape of the cavity? How is it 
formed? Is the cavity apparently anything 
more than a depression of the surface of the 
thallus ? How much of the width of the section 
(thickness of the thallus) does a conceptacle 
occupy? Notice the cluster of hairs or tri- 
chomes in the conceptacle. What is their rela- 
tion to the opening or ostiole of the concep- 
tacle ? "What part of the conceptacle forms the 



ROCK WEED 293 

elevation noticed on the surface of the thallus ? 
Examine under the high power. From what 
part of the conceptacle do the hairs grow % 
"What is their structure ? Are they simple or 
branched ? What tissue forms the wall of the 
conceptacle ? Do you find anything but hairs 
in these conceptacles ? Examine both transverse 
and longitudinal sections to get views of con- 
ceptacles from different directions. Look over 
your sections for conceptacles in various stages 
of formation. Are they formed in the same 
manner as vesicles ? Draw. 
2. The male conceptacles. — With a razor cut 
transverse sections through the end of an alco- 
holic branch bearing male conceptacles, and ex- 
amine under a low power. What is the shape 
of the section ? What sort of tissue occupies 
the centre? The edge? In what part of the 
section do you find the conceptacles? Does 
their position correspond with that of the ster- 
ile conceptacles ? Do you find the same parts, 
ostiole, hairs, etc., as in the sterile conceptacles ? 
How do the male compare with the sterile con- 
ceptacles in size ? Draw. 

Study the sections under the high power. Ex- 
amine again the tissue composing the centre of 
the section. Of what kind of cells is it formed ? 
How are they joined together ? What do they 
contain ? Do these cells entirely fill the centre 
of the section? Can you now account for the 
feel of the end of the branch when passed be- 
tween the fingers? Examine the hairs. Are 
those which fill the cavity of the conceptacle 
at all different from those which project through 



294 THE BIOLOGY OE THE PLANT 

the ostiole ? Notice attached to the former small 
ovoid cells, the antheridia. To what part of 
the hairs are the antheridia attached ? Do you 
find more than one antheridium borne on a sin- 
gle hair ? Notice the contents, the anthero- 
zoids, of the antheridia. 
Draw a conceptacle as seen under the high power. 
Draw also several hairs with their attached antheridia, 
and some of the cells forming the central tissue. 

3. The female conceptacles. — Prepare sections 
showing female conceptacles. Study these as 
directed above, and compare the sections in 
every respect with those containing the male 
conceptacles. Compare the female with the 
sterile and the male conceptacles as regards 
form, size, contents, etc. Examine especially the 
oogonia. What is their shape ? How do they 
compare in size with the antheridia ? Are they 
borne upon hairs like the latter ? If not, how 
are they held in place within the conceptacle ? 
How does the number of oogonia compare with 
the number of antheridia in a conceptacle ? Has 
each oogonium a covering? If so, what is its 
structure ? Can you detect any outgrowths, e. g., 
cilia, on it ? Do you find the contents of any 
of the oogonia to be divided in several parts or 
oospheres? If so, how many such parts can 
you distinguish in a single oogonium? Does 
each part have a nucleus ? Is each part a cell ? 
Mount a section in a drop of fresh water. What 
happens to the coverings of the oogonia ? 

How are the male and the female concepta- 
cles distributed in the same or in different 
plants? What is their relation to the sterile 



ROCKWEED 295 

conceptacles ? Do you ever find oogonia and 
antheridia in the same conceptacle ? 
Draw the section as seen under the low power, and 
the conceptacle and a single oogonium as seen under 
the high power. 

PHYSIOLOGY 

a. The fertilization of the oosphere. — From plants that 
have been hanging in the air collect a drop of 
the orange-colored fluid that exudes from the male 
conceptacles. Mix this drop with a drop of sea 
water and examine under the high power. Note 
the antheridia floating in the drop. Look for 
antherozoids actively swimming about. What 
is their shape? Color? Structure? By what 
means do they swim ? Apply a drop of iodine if 
necessary. Are they at all like the antherozoids 
found in Charcot Draw. 

Mount in a similar manner a drop of the olive- 
colored fluid issuing from the female concepta- 
cles. Look for oogonia. Try to find an oogo- 
nium whose wall is dissolving, thus setting free 
the oospheres. Do the oospheres change in 
shape before being liberated ? What is their 
structure? Can you detect a nucleus? Have 
they any means of locomotion ? Draw. 

After finding some mature oospheres, mix on 
the slide with the water containing them a drop 
containing antherozoids. Study the behavior of 
the antherozoids and try to see as much as pos- 
sible of the union of two kinds of cell (fertiliza- 
tion). Draw. 



296 THE BIOLOGY OF THE PLANT 

General Questions. — Are the methods of reproduction 
of rockweed likely to lead to its wide distribution? 
Compare with Char a and Yaucheria in this respect. Is 
the plant structurally adapted to endure long exposure 
to the air without serious injury % 



Mould (Penicillium Sp.) 

Material. — Examine stale bread or cake, shoe-black- 
ing, old leather, ink, preserves, etc., for the common blue 
mould. If none be found, specimens may easily be raised 
by moistening a piece of bread, covering it with a bell- 
jar, and allowing it to stand in a warm place for about a 
week. At the end of that time the bread will probably 
be covered by a fine crop of moulds, and among them 
the kind wanted. A decoction of prunes may be left 
standing exposed to the air for a time, and Penicillium 
will almost certainly make its appearance. 

Schulze's solution, iodine, potash, Pasteur's solution 
with sugar, watch-glass, fine forceps, hand -lens, com- 
pound microscope, moist chamber, twenty per cent, glyc- 
erine, and thirty per cent, alcohol will be needed. 

Method of Examination. — Look for Penicillium grow- 
ing naturally. Try to find how many different sub- 
stances it infests. Compare specimens developed natu- 
rally with those raised by cultivation. 

MORPHOLOGY 

Naked- eye Characters. 

a. General appearance. — Examine the coating of mould 
found on the infested material. Do you find the 
mould to be in several masses or in one ? What is 
the color of the mould ? Do you find any varia- 
tions of color ? If so, do the various colors shade 



298 THE BIOLOGY OF THE PLANT 

into one another ? Do these different shades have 
any definite relation to the centres of the masses 
of mould ? How high above the surface does the 
mould rise ? Can you with a lens distinguish the 
individual stalks or aerial hyph.se, each with a 
tuft-like head, the conidiophore ? Examine with 
a lens and note the root-like threads forming the 
mycelium, which runs over the surface of the 
substratum. With the fine forceps pick up a 
small mass of mould. Is it attached to the sub- 
stratum or is it merely lying on the surface ? 

Tap a piece of mouldy bread and notice the 
cloud of dust, the spores, given off. 

Microscopic Characters. 

a. The mycelium. — With the fine forceps place some 

of the mycelium on the slide in a drop of water, 
twenty per cent, glycerine or thirty per cent, alco- 
hol. Does water readily wet the mould? Using fine 
clissecting-needles, gently pick to pieces the mass 
of mould, and examine under both the low and 
the high powers. What is the structure of the 
mycelium ? Do the threads, the mycelial hy- 
phae, branch ? If so, are the branches given off 
at definite points? Do the hyphaB consist of a sin- 
gle cell or of several cells ? Do the hyphaB vary in 
diameter ? What is their shape at the end ? What 
is the structure of the cell- wall? What do the 
hyphaa contain ? Examine mycelium of the dif- 
ferent colors. What variations in structure and 
state of development do you find ? 
Make several drawings to illustrate the various ar- 
rangement of the mycelial hyphaB and their structure. 

b. The aerial hyphae. — At what points do the aerial 



MOULD 299 

hyphse originate? How do they compare with 
the others in shape, size, structure, etc. ? Do they 
branch ? If so, at what points ? Do you find 
more than one branch given off at one point ? 
Do the cavities of the aerial connect with the 
cavities of the mycelial hyphge? Are the cavi- 
ties of the branches in communication with the 
cavity of the main stalk ? 

c. The conidiophores. — Study the structure of the 

terminal branches or conidiophores. Note that 
each tapers to a short, slender stalk, or sterigma, 
w T hich bears a series of spherical or oval spores, the 
conidia. Draw. Study a single stalk of coniclia. 
Does it branch? Do you find any variations in 
shape, size, and color among the conidia of the 
same stalk ? If so, what position on the stalk do 
the larger conidia occupy ? Do you find any 
conidia which are not yet fully formed ? If so, 
what is their position on the stalk ? Judging 
from the facts just observed, what do you think 
is the manner in which the conidia are formed ? 
Study the structure of a single spore, using such, 
reagents as are necessary. Does it resemble in 
any way the cells of yeast ? Draw. 

d. The sporocarp. — It is not likely that the student 

will be able to find this organ on Penieillium 
and work out its structure successfully. The 
sporocarps of Eurotium, which usually grows with 
Penieillium, may be used instead. These will 
be found as small, bright-yellow bodies situated 
among the mycelial threads. Examine one of 
them under both powers. Note how it is at- 
tached to the mycelium. Study the structure 



300 THE BIOLOGY OF THE PLANT 

of the outer wall. Draw. Crush the wall by 
pressing upon the cover-glass and notice the con- 
tained sacs, the asci. How many does a single 
sporocarp contain? What is the shape of an 
ascus? What is its structure? How many spores, 
the ascospores, does each ascus contain ? What 
differences can you detect between these spores 
and the conidia ? Draw an ascus with its spores. 
Look for sporocarps in various stages of growth. 
They develop from two branches which become 
twisted around each other in the form of a short 
spiral. Draw all of the stages found. 

PHYSIOLOGY 

a. The germination of the conidia. 

Prepare a moist chamber, using a drop of Pas- 
teur's fluid with sugar for the hanging drop. With 
the fine forceps pick up a few aerial hyphaB with 
conidiophores, and sweep the conidiophores over 
the surface of a drop of water on a slide so as to 
brush off some of the conidia into the drop. Then 
dip the point of a needle first into the drop of water 
and then into the hanging drop, thus transferring 
Si few conidia to the latter. Examine the conidia 
from time to time for three or four days. How 
long before you can detect signs of germination ? 
What is the first change noticed? How many 
hyphas does each spore form ? Do these hyphae 
branch ? Do they interlace to form a mycelium ? 
Do the mycelial hyphaa unite ? 
Draw the various stages of germination. 

General Questions. — How do you account for the very 
wide distribution of blue mould ? For its occurrence in 
cans of preserves ? 



Mushroom (Agaricus Sp.) 

Material. — Mushrooms are usually abundant in past- 
ure lots in the late summer and early fall. They fre- 
quently grow in gardens. In greenhouses they may be 
found at various times during the year. They may 
often be obtained from gardeners who raise them for 
the city trade. In case mushrooms cannot be obtained, 
almost any of the common toadstools will do as well. 
Get specimens showing as many different stages of 
growth as possible. Both fresh and alcoholic material 
will be used. The latter is prepared by hardening the 
mushrooms in one per cent, chromic acid for a day, 
washing off the superfluous acid in fresh water for two 
or three minutes, then placing them for about twelve 
hours in each of the following grades of alcohol — forty, 
sixty, seventy-five, and ninety per cent. A part of the 
alcoholic material may be examined entire and the rest 
of it sectioned. Specimens to be sectioned should be cut 
into pieces not more than a half-inch square before be- 
ing placed in the chromic acid. 

Apparatus and reagents required : dissecting-needle, 
bell-jar, watch-glass, compound microscope, lens, razor, 
fifty per cent, glycerine, acetic acid, hydrochloric acid, 
carmine, and Schulze's solution. 

Method of Examination. — If the student have access 
to living specimens growing naturally, let him study 
their surroundings, the kind of soil upon which they 



302 THE BIOLOGY OF THE PLANT 

grow, their mode of attachment to the soil, the number 
of individuals growing together, etc., etc. Specimens 
may then be removed to the laboratory and studied 
without and with the microscope. Preserved material 
should be examined in a dish of seventy-five per cent, 
alcohol. 

MORPHOLOGY 

Naked -eye Characters. — Select several mushrooms or 
toadstools, and study 

a. Shape. — What is the general shape ? Do you find 

any marked variations from this ? Do you find 
that the mushroom always has the same shape as 
the mature specimen ? If not, what changes of 
shape does it go through during its development ? 

b. Size. — What is the height of a mature specimen? 

What variations do you find? Does the mush- 
room attain its mature form before or after it 
reaches its full height? 

c. Structure. — Examine a mature specimen and make 

out the following parts, the expanded top or 

pileus, and the stalk or stipe, surrounded by a 

ring, the anxmlus. Study each part in succession. 

1. The pileus. — What is its shape? Diameter? 

Thickness? Color of the upper surface? What 

is the structure of the upper surface ? Can you 

give any reasons for this structure ? Examine 

the extreme margin of the pileus for a thin 

membranous expansion. What is the color of 

the under surface? Note that it varies from 

pink in young to dark-brown or black in old 

specimens. Note also the gills or lamellae. 

How are they arranged ? What is their shape \ 



MUSHROOM 303 

Structure ? Color ? Cut vertically through the 
middle of the pileus. What is the nature of 
the inside ? 
Draw the pileus as seen from above, from below, and 
in section. 

2. The stipe. — What is its shape? Does it have 

the same diameter throughout? Wbat is its 
color? Does it have the same color in all speci- 
mens ? How is it attached to the pileus ? Is it 
attached to the gills ? Examine the lower end 
of the stipe. How is it attached to the soil? 
Can you find any roots ? Use a hand-lens and 
look for the remains of the mycelium, from 
which the aerial part of the plant (the " mush- 
room " proper) arises. As the mushroom de- 
velops, does the stipe increase the more in 
diameter or in length ? Make transverse and 
longitudinal sections through the stipe, and 
compare its structure with that of the pileus. 
Draw. 

3. The annulus. — What is its shape? How far 

from the pileus does it grow ? Examine its 
structure, and compare it with that of the mem- 
brane on the margin of the pileus. Examine a 
series of specimens to see that the annulus and 
the membrane are at one time connected, and 
form the veil or velum. At what time and 
how do they become separated ? Has the velum 
any definite function ? Study a series of speci- 
mens, and draw the different stages of develop- 
ment. 

Microscopic Structure. 

a. The mycelium. — Eemove from the soil a young 



304 THE BIOLOGY OF THE PLANT 

mushroom, leaving some of the earth adhering to 
the mycelium. Cut off the lower end of the stipe 
and place it with the mycelium in a watch-glass 
of water. Carefully wash and pick away as 
many as possible of the earthy particles, place 
the preparation on the slide in a drop of water 
or of dilute glycerine, and examine. Notice 
the white threads visible without the microscope. 
Are these bands of hyphas or individual threads ? 
Note the interlacing of the mycelial hyphaB. 
What is the structure of these ? What do they 
contain ? Look for rod-like crystals. Are they 
within or without the Iryphae. Test these with 
acetic acid. Do the crystals dissolve ? If so, they 
consist of carbonate of lime. If the crystals do 
not dissolve in acetic, test them with hydrochloric 
acid. If thej 7 dissolve, they consist of oxalate of 
lime. 

Endeavor to make out how the lower end of 
the stipe is attached to the mycelium. Can you 
trace mycelial hyphas running into the stipe ? 
Draw several portions of the mycelium to show its 
structure and arrangement. 

h. The stipe. — Make a longitudinal section passing 
through the middle of the stipe and the annulus. 
Examine under a low power. Can you distin- 
guish tissues in the stipe ? Is its centre more or 
less dense than its margin ? From what part does 
the annulus arise ? Put on the high power. No- 
tice that the stipe consists of rows of hyphas, each 
hypha being divided into a number of cells by 
cross walls or partitions, the septa. In what di- 
rection do these rows run ? Do they interlace to 



MUSHROOM 305 

any great extent ? Do they branch ? Examine 
the individual cells. "What is their shape? Ar- 
rangement ? Structure of their walls ? What do 
the cells contain ? How do those near the centre 
of the section compare in diameter with those at 
the margin? Does the annulus have the same 
structure as the stipe ? In what direction do the 
end walls of the cells run? Compare a single 
row of cells with a hypha. Is the stipe anything 
more than a mass of hyphse ? Stain the section 
with Schulze's solution. Note the color assumed 
by fungus cellulose. Is it the same as ordinary 
cellulose ? Do the cells contain starch ? Draw 
your sections, showing all of the features ob- 
served. Make a transverse section of the stipe, 
and examine in dilute glycerine. Compare with 
the longitudinal section. Note the large, nearly 
circular, intercellular spaces. Where are they 
most numerous ? What is the shape of the hy- 
phae in trans-section ? Do they vary in diameter ? 
If so, where are the largest ? Notice that some 
of the hyphaa show in the centre a highly re- 
fractive spot. Can you find any trace of this on 
the end walls in the longitudinal section of the 
stipe ? Draw. 

g. The pileus. — Make a vertical section passing 
through the middle of the pileus and of the stalk, 
and examine under a high power. Is the struct- 
ure of the mass of the pileus the same as that of 
the stipe ? What course do the hyphse take upon 
entering the pileus ? Do the hyphaa extend into 
the gills ? Make a diagram showing the course 
of the hyphse through the entire plant. Make 
20 



306 THE BIOLOGY OF THE PLANT 

another vertical section passing through the pi- 
leus to one side of the stipe and through the gills 
in such a way as to divide the latter transversely. 
Examine under the low power. How are the 
lamellae attached to the pileus? Do their "tis- 
sues " seem to be continuous ? Draw. Examine 
under the high power. Endeavor to make out 
the central portion, or trama, the sub-hyme- 
nial layer, and the outer portion, or hymenial 
layer, of each gill. What is the structure of the 
trama? In what ways does it differ from the 
central part of the stipe and the pileus ? What 
is the course of the hyphaa? How do you distin- 
guish the sub-hymenial layer ? How do its cells 
differ from those of the trama? What is the 
structure of the hymenial layer? What is the 
direction of its cells ? Are they continuous with 
those of the next layer below ? Study this layer 
closely, and endeavor to make out that it consists 
of two kinds of cells, those with rounded ends, 
the paraphyses, and the basidia, ending in two 
pointed processes or sterigmata. How are the 
paraphyses and basidia arranged with regard to 
each other ? Can you think of any use which the 
former may have ? How do they differ in shape ? 
Note the rounded body, the basidiospore, 
borne by each sterigma. Examine -sections from 
young mushrooms to find the paraphyses, basidia, 
and spores in various stages of development. Note 
how the sterigma and its spore are formed. Make 
a diagram showing the arrangement of the tissues 
of the lamella. Draw several isolated paraphyses 
and basidia. 

Break off the pileus of a mushroom whose 



MTJSHEOOM 307 

gills are dark-brown or black, lay it, gills down- 
ward, on a piece of white paper, and cover with 
a bell-jar or tumbler. After five or six hours re- 
move the pileus, and note the " print" of its under 
surface made upon the paper by the spores. To 
what do the dark lines correspond? To what the 
white ? With a needle place some of these spores 
in a drop of water, and examine under the high 
power. What is their shape ? Structure ? Color ? 
Draw several. Pull off a single gill and lay it on 
a slide without the drop of water and cover-glass. 
Note the spores, many of them detached from 
the sterigmata. What is the color of the tissue 
of the gill? To what is the color of the under 
side of the mushroom due ? 



General Questions. — Eeview the whole structure of 
the mushroom. Do you find the aerial fruiting portion 
to be anything more than a collection of hyphas, at the 
tips of some of which spores are borne ? In what va- 
rious ways do the blue mould and the mushroom resem- 
ble each other? What do you consider to be essentially 
their points of difference? Can the blue mould and the 
mushroom obtain their food in the same manner as 
green plants ? Are they dependent upon the sunlight ? 



Liverwort {Marchantia Sp.) 

Material. — Though this plant may frequently be found 
growing in the grass or on rocks in damp, shady places, 
especially near springs, or where the water is dripping 
down a stony embankment, it is most easily obtained at 
the greenhouses. It grows on the soil in the rose-beds, 
and the various stages may be found at one time. Good 
specimens bearing the three kinds of fruiting organs are 
generally abundant in the fall and in early spring. The 
male plants with their flat-topped umbrella-shaped stalks 
usually grow near the female plants, which may be dis- 
tinguished by the star-shaped tops which the fruiting 
stalks bear. When a good supply of fruiting specimens 
is found they should be preserved in alcohol, for fear 
that fresh ones may not be obtainable when wanted. 
Both fresh and alcoholic material will be studied. Liv- 
ing specimens should be removed to the laboratory 
along with plenty of the earth to which they are at- 
tached. Place them in flower-pots or dishes filled with 
loose, damp soil, and cover with a plate of glass or a bell- 
jar. Do not place the plants w r here the sun is too hot, 
as they are very likely to be " scorched " and killed. 

Besides the specimens the student will need the com- 
pound microscope, hand-lens, razor, forceps, watch-glass, 
pipette, fifty per cent, glycerine, Schulze's solution, iodine, 
pith, and dissecting-needles. 

Method of Examination— Study the plant as it grows 



LIVERWORT 309 

in the grass, on the rocks, or in the greenhouse. No- 
tice what sort of soil it occupies and the general char- 
acter of its surroundings. Examine the gross anatomy 
of the plant, then make sections and study its internal 
structure. 

MORPHOLOGY 

Naked-eye Characters. 

a. General appearance. — Examine first a plant bear- 
ing none of the upright stalks which produce the 
sexual organs. What is the general shape of 
the body (thallus) of the plant ? What part of 
the thallus is in contact with the ground ? Does 
the thallus present well-marked dorsal and ven- 
tral sides ? Compare with rockweed. What is the 
color of the thallus ? Width? Thickness? Tear 
a thallus to pieces and note its texture. Does it 
have a midrib ? Compare with rockweed. Does 
the thallus bear horizontal branches ? If so, in 
what manner are they given off ? Compare with 
rockweed. Do certain parts of the thallus appear 
to be older than others ? If so, where are these 
parts ? Compare with rockweed. In which di- 
rection does the thallus grow? Compare with 
rockweed. Examine next a plant bearing the 
upright fruiting stalks. At what points do these 
stalks grow? Is this position constant? Aside 
from the stalks, do these plants differ in any es- 
sential particular from those which are without 
stalks ? Examine a number of plants to find the 
two kinds of fruiting stalks, the male or anthe- 
ridial branch, with a flat, and the female or 
archegonial branch, with a star-shaped expan- 
sion at the top of each stalk. Do the male and 



310 THE BIOLOGY OF THE PLANT 

female stalks occur on the same plant ? Are 
they always borne upon the same side of the 
thallus ? Do you always find the same number 
on each plant ? What is their relation to the 
midrib ? What is the shape of the stalk of the 
fruiting branches? Look for grooves running 
lengthwise along the stalk. How many do 
you find ? What is their position ? Examine 
both surfaces of the expanded portion or recep- 
tacle of each. Note the ridges on the receptacle 
of the antheridial stalks. How many are there ? 
Are they on both sides ? Compare in all re- 
spects with the archegonial branches. Look for 
the two kinds of fruiting branches in different 
stages of growth. What changes in shape and 
size do they go through in the course of their 
development ? 

Look closely at the upper surface of the thal- 
lus for small, cup-like outgrowths, the cupules. 
What is their position? Does it have any par- 
ticular relation to the midrib or to any other 
part of the thallus ? Are the cupules evenly dis- 
tributed over the surface ? What is their shape ? 
Look for small, green, non - sexual reproductive 
bodies, the gemmae, inside the cupules. Do all 
of the cupules contain gemmae ? Are the cupules 
borne upon a stalk % Are they borne upon the 
same plants as have the fruiting branches ? Do 
you also find cupules upon plants which bear no 
fruiting stalks? With a hand -lens examine a 
cupule and note the shape of its margin and the 
position of the gemmae. With a lens study the 
upper surface of the thallus and note that it is 
marked off into small areas, the areolae. In 



LIVERWORT 311 

the centre of each area look for a small circu- 
lar opening, the stoma. Examine the under 
surface of the thallus for root-like filaments, the 
rhizoids. Are they abundant or few ? Do they 
grow from any definite area of the under sur- 
face ? Do they grow at the tips of the branches ? 
What is their average length? Do they hold 
the plant closely to the soil? What is their 
color? Do they at all resemble the rhizoids seen 
on Chara ? Look among the rhizoids for purple 
leaves following the line of the midrib. Do 
you find areolae and stomata on this sur- 
face? 
Make sketches of plants showing all of the features 
studied. 

Microscopic Structure. 
a. The tissues of the thallus. — Hold a piece of the 
thallus of a living plant between two pieces of 
pith, and with a sharp razor cut a series of thin, 
transverse sections. Lay several of these on a 
slide in a drop of water or fifty per cent, glycerine 
and examine with the low power. If it is found 
that the tissues of the living plant contain so 
much air as to obscure the structure, use the sec- 
tions of the fresh specimens only to get a general 
idea of the structure, then work out the details 
in alcoholic material. Notice the shape of the 
section. How do you locate the midrib ? Notice 
also that the section shows its upper surface to 
be composed of a layer, the " epidermis," of clear 
cells showing elevations (sections of stomata) here 
and there. Below this layer comes another con- 
sisting of dark-green cells, and this is succeeded 



812 THE BIOLOGY OF THE PLANT 

by a rather thick mass of large, clear cells, some 
of which contain brown oil globules. Notice 
also the rhizoicls. 
Make a diagram showing the position of all these 

parts. Put on the high power and study these parts 

separately. 

Of how many layers of cells does the " epider- 
mis" consist? What is their shape as seen side- 
wise ? Do they contain chlorophyll ? What is 
their arrangement at a stoma ? Notice that air- 
bubbles are frequently present in the tissues, es- 
pecially under the stomata. What is the shape 
of the cells in the green band ? Are they closely 
or loosely packed together? Is their green color 
due to the fact that their chlorophyll bodies are 
larger or that they are more numerous than else- 
where in the plant ? Can you give any reasons 
for the presence of this band of cells in this par- 
ticular portion of the thallus ? Are any of these 
cells apparently branched ? 

Examine the nearly colorless cells making up 
the greater part of the section. What is their 
shape ? Do you find them so arranged as to 
leave many intercellular spaces ? What do these 
cells contain? What portion of the midrib do 
they form ? Do any of these cells show pit-like 
markings in their walls ? 

b. The rhizoids. — With the fine forceps tear off a 
bunch of rhizoids. How many kinds do you find ? 
How do you distinguish them? What is their 
structure? Examine your sections for rhizoids. 
From what cells in the thallus do they grow? 
What do the rhizoids contain ? 



LIVERWORT 



313 



c. The "leaves." — Note also the sections of the 

" leaves " among the rhizoids. "What is the struct- 
ure of these bodies ? 
Draw portions of your sections to show the structures 
studied. 

Make longitudinal sections through the th alius and 
compare them with the sections just studied. Draw. 

d. The stomata. — Select a flat thallus, lay a portion 

of it on a slide, and examine with a high power. 
Note the distribution of the stomata. Select a 
single well-formed stoma and study its structure. 
What is the shape of the stoma ? Of how many 
cells is its rim formed? What is their shape? 
How are they arranged ? Do they contain chlo- 
rophyll? Focus down into the cavity of the 
stoma and note the guard cells, which project 
into and partly close the opening of the stoma. 
Examine the under surface of the thallus for 
stomata. From the same or another flat thallus 
make tangential sections, i. e., sections parallel to 
the flat surface of the thallus, so as to remove 
only the " epidermis." Examine these with the 
high power and compare with the other prepara- 
tions which show the structure of stomata. Parts 
of the section will probably show the manner in 
which the green cells lying immediately under 
the " epidermis " are divided into groups. 
Draw a sectional and a surface view of a stoma. 

e. The fruiting organs. 

1. The cupules and gemmae. — With a dissecting- 
needle pick out of the cupules some of the gem- 
mae, mount them in a drop of water, and ex- 
amine under a low, then a high power. What 



314 THE BIOLOGY OF THE PLANT 

is their shape? Of what kind of tissue are 
they composed? Are they of the same thick- 
ness throughout ? Do the cells have the same 
contents as those of the thallus ? Examine the 
margin of a single gemma and find the scar at 
the point where the gemma was attached to its 
pedicel or stalk. What is the shape of the 
scar ? What is the arrangement of the neighbor- 
ing cells ? Find also two vegetative notches. 
How are they situated in reference to each 
other and to the scar? How do you distin- 
guish them from the scar? What is the posi- 
tion of the margins of the gemma on each side 
of the notch ? Examine the base of the notch 
in large, mature gemma3 for small papillae, 
which are the early stages of the young plants 
to which the gemmae give rise. Why should 
these organs be called "gemmae"? Having 
examined one surface of a gemma, turn it over 
and examine the other side. Are the two sides 
unlike ? In what ways may gemmae be distrib- 
uted? What position would they naturally 
assume upon the ground? Is their structure 
at all related to the manner in which they pro- 
duce new thalli ? 

Draw several gemmae of various sizes. Cut 
off a cupule and mount it in a drop of water. 
Examine it with a low power. Notice again 
the shape of its margin. Put on a high power 
and study the structure of the cupule, noting 
the gemmae on the inside, and its toothed mar- 
gin. Draw. Examine a young cupule. How 
does it differ in structure from the mature or- 
gan ? Draw. Make transverse sections through 



LIVERWORT 315 

a thallus, passing through the cupule, and 
mount in fifty per cent, glycerine. Study the 
wall of the cupule. What is its structure ? 
Of how many layers of cells does it consist ? 
Note the base. Examine the gemma? inside the 
cupule. To what part of it are they attached ? 
How are they attached ? In what direction do 
they stand ? What is the structure of the ped- 
icel ? Look for gemma? of various sizes. Can 
you trace them down to two-celled papilla?? 
Study a number of sections to see that a 
gemma develops from the division of the upper 
cell of a papilla, while the lower cell remains 
as the pedicel. Do you find any unicellular 
papilla? ? Draw. 
2. The antheridial branch. — Make transverse 
sections of the stalk. What is its outline ? 
What is the position of the grooves ? Of what 
sort of tissue is the stalk composed? Does it 
have an epidermis ? Do its cells contain chlo- 
rophyll? What is the arrangement of the 
margins of the groove? Note in the grooves 
the rhizoids, seen in cross-sections. Are there 
many or few ? What is their outline ? Note 
the peg-shaped outgrowths projecting into 
their cavities. Compare this view with a lon- 
gitudinal view of a rhizoid. Notice also the 
sections of scales in the groove. Do you find 
them elsewhere in the section ? Compare with 
those seen on the under side of the thallus. 
Draw the section. Select a large, well-developed 
antheridial branch, and make a vertical section 
which passes down through the middle of the 
receptacle and stalk. Mount in water or glyc- 



316 THE BIOLOGY OF THE PLANT 

erine and examine under the low power. What 
is the shape of the section? Note in the re- 
ceptacle flask-shaped, dark-colored masses, the 
antheridia. Of what tissues is the receptacle 
composed? Compare with the thallus. Do 
you find scales, rhizoids, etc., on the section? 
If so, to what part are they confined ? Exam- 
ine under the high power. Note that each an- 
theridium is contained in a well-defined cavity. 
What is the shape of an antheridium? Does 
it have a stalk ? What is the structure of the 
wall of the antheridium ? Do the cells contain 
chlorophyll? How are the cells arranged? 
Can you make out its contents ? Do you find 
unicellular papilla?, the paraphyses, at the 
base of the antheridium? How does the an- 
theridium communicate with the exterior ? 
Do the antheridia vary in size and develop- 
ment in different parts of your section? If 
so, where are the oldest? Draw the section. 
If living material containing mature antheri- 
dia be used, some of the sections will probably 
show escaping antherozoids. If so, study 
their structure and movements. Compare 
them with the antherozoids of Chora and 
Fucus. Draw. 

Make a horizontal section of the surface of 
the antheridial receptacle, and examine under 
the high power. Do you find that it has 
the same structure as the surface of the thal- 
lus? Note the smaller openings or pores, 
leading to the antheridial cavities. Do these 
pores differ in structure from the stomata? 
Draw. 



LIVERWORT 317 

How many points of resemblance in struct- 
ure can you discover between an antheridial 
branch and a thallus ? 
3. The archegonial branch. — Make sections of 
the archegonial, and compare them with the 
sections of the antheridial branch. Do you find 
any marked differences in shape, size, structure, 
etc. ? Do you find the same tissues to be pres- 
ent and similarly arranged? Draw the sec- 
tions. Kemove one of the arms of the archego- 
nial receptacle, make transverse sections of it, 
and compare the structure with that of the 
stalk. Examine vertical sections, and find on 
the lower surface of the receptacle the flask- 
shaped archegonia with elongated necks. No- 
tice how these are distributed through the sec- 
tion. Do you find them to be arranged in pairs, 
with a wing-like down-growth (sections of the 
perichaetium) on each side? Draw. 

Study the structure of a single archegonium 
which has been fertilized. These may usually 
be distinguished from others by the fact that 
the lower portion contains a dark-brown mass. 
Make out the stalk, the body, and the elon- 
gated neck. What is the structure of the stalk ? 
From what does it arise ? Does it resemble the 
stalk of an antheridium? Surrounding the 
stalk look for the section of a cup-shaped mass 
of cells, the perigynium. How much of the 
archegonium does the perigynium cover? "What 
is its structure ? What is the shape of the body 
of the archegonium? What is the structure 
of its wall? What does it contain? Do the 
contents entirely fill the cavity? Can you 



318 THE BIOLOGY OF THE PLANT 

make out the structure of the contents ? How 
is the neck formed ? How does it compare in 
length and diameter with the body? Draw 
a single mature archegonium. Examine the 
section for younger, unfertilized archegonia. 
Where do you find them ? Does their position 
correspond with that of the immature antheri- 
clia ? Draw several young archegonia to show 
the various stages of their development. Com- 
pare the young with the older archegonia. 
Look on older receptacles for the ripening 
archegonia, or sporogonia, and study their 
structure. What changes have taken place in 
the perigynium, in the neck, and in the body ? 
Draw. Crush a living sporogonium and exam- 
ine the spores and spirally- marked elaters. 
Mount them without the drop of water and ex- 
amine, then allow a small drop to flow under 
the cover, being careful to keep watch of the 
elaters. What change takes place in them 
when they are moistened ? Of what use may 
this be? Draw some of the spores and elaters. 



PHYSIOLOGY 

a. The fertilization of the 06 sphere. 

If antheridia and archegonia of the proper age 
be obtained, it will not be difficult to watch cer- 
tain stages of the process of fertilization. Make 
vertical sections of the two receptacles, bearing 
respectively mature antheridia and archegonia, 
and mount them in the same drop of water. 
Note the motions of the antherozoids, their jour- 



LIVERWORT 319 

ney to the necks of the archegonia, and their be- 
havior after reaching the latter. Can you give 
any reason why the anthericlia are on the upper, 
and the archegonia on the under side of the re- 
ceptacle? 



Fern {Aspidium Sp. or Fteris Sp.) 

Material. — Ferns are almost everywhere abundant in 
woods, meadows, and along the roadside, edges of fields, 
etc. Some specimens should be taken in the early 
spring as the fronds are coming out of the soil, others 
in the early summer when the vegetative fronds are 
mature, and still others later in the summer and in the 
early fall, when the spores are to be found in different 
stages of formation. Prothallia are to be looked for on 
mossy logs and rocks and on the soil at the base of the 
fern plant. Some of the specimens should be pressed 
as for an herbarium, and others preserved in alcohol. 
Species closely related to, or even identical with, our 
wild forms are to be had at almost all greenhouses, and 
are available in midwinter. Their prothallia are usually 
abundant on the soil of the neighboring flower-pots and 
beds, or adhering to the surface of the flower-pots them- 
selves, particularly of those which are covered with a 
film of vegetable growths. Wild ferns may be kept 
in a greenhouse if wanted for examination in winter. 
Their prothallia may be raised from spores strewn upon 
the surface of clean, damp sand. The cultures should 
be examined every few days, and the different stages of 
development studied as they become available. The 
young fern plants will develop from the prothallia in 
about six or eight weeks. The prothallia may be picked 
off the surface of the sand with needles and examined 
in a drop of water. They may be preserved by being 



FEKN 321 

placed in a saturated solution of picric acid for six or 
eight hours, washed for a few minutes in thirty per 
cent, alcohol, and then hardened in the various grades 
of alcohol. In addition to the plants the student will 
need the compound microscope, hand-lens, forceps, ra- 
zor, dissecting-needles, watch-glass, scalpel, ten per cent, 
hydrochloric acid, dilute glycerine, Schulze's solution, 
Schulze's macerating mixture, acetic acid carmine, hae- 
matoxylin, picric acid, alcohol lamp, pith, and fifty per 
cent, alcohol. 

Method of Examination. — Living plants should first 
be studied in their various relations to their surround- 
ings. Dried specimens are good for the study of the 
gross anatomy, especially of the frond. Alcoholic mate- 
rial should be examined in fifty per cent, alcohol. The 
rhizome and fronds should be sectioned in various direc- 
tions, and the disposition of the different tissues studied. 
Sections for microscopic examination are also needed. 
Material preserved in strong alcohol must be soaked 
one to four hours in seventy- five per cent, alcohol be- 
fore sections are cut. 

MORPHOLOGY 

A. — The Spore-bearing or Asexual Plant. 
Naked-eye Characters. 

a. General appearance. — Study a well-developed spec- 
imen as it grows in the soil, and note that the 
aerial portion consists mainly of long -stalked 
leaves, the fronds. On their upper portions the 
stem or rachis of each frond bears lateral out- 
growths or appendages, the pinnae, resembling 
leaflets. Each pinna is subdivided into smaller 
portions, the pinnules. On the back of the pin- 
21 



322 THE BIOLOGY OF THE PLANT 

nules are found circular brown dots, the sori, each 
of which, on being examined with a lens, is seen to 
consist of a membranous expansion or indusium, 
covering a group of small stalked bodies, the spo- 
rangia, in which on microscopical examination 
are found the spores. Among the bases of the 
fronds of the current year will be found many 
dried stalks, the remains of leaves of previous 
years. Upon removing the plant from the soil 
and washing it in water it will be seen that the 
leaves arise from a stem-like portion or rhizome, 
which creeps along just below the surface of the 
soil and gives off roots. 

b. Structure. — Eemove a plant from the soil, wash the 
roots, and study the following parts : 
1. The rhizome. — What is its general shape ? Does 
it branch? Cut the rhizome across, midway 
between its ends. What is the shape of the 
outline? From what part of the rhizome do 
the roots arise? From what part the fronds? 
Are these positions constant ? Do you find any 
other structures than roots and fronds borne 
by the rhizome? Does the rhizome appear to 
be made up of segments, as nodes and inter- 
nodes? If so, how do you distinguish the 
nodes ? On what part of the rhizome are the 
leaves of the current year borne ? The remains 
of leaves of past years? What is the general 
structure of that end of the rhizome which is 
near the leaves of the current year ? What is 
the color of the margin of the rhizome, as seen 
in the cross-section? Of the greater portion of 
its centre? Do you find near the centre any 



FERN 323 

parts which are of a different color from the 
surrounding tissue ? From the margin ? If so, 
how many of each kind are there, and how are 
they arranged ? 
Make a drawing of the cross-section, showing its shape 

and the position of the various tissues. 

Divide a portion of the rhizome through the 
middle lengthwise. How do you find its tis- 
sues to be arranged ? Look for strands of 
fibrous tissue. In w T hat direction do they run ? 
With a fine scalpel carefully remove the tis- 
sue surrounding these strands. What is their 
arrangement in the rhizome ? Do they enter 
the leaves and roots ? These strands may be 
more easily traced if the rhizome be soaked for 
a few hours in ten per cent, hydrochloric acid. 
This macerates the softer tissues, which may 
then be picked away from the fibrous bundles. 
Make a drawing showing the arrangement of these 

bundles. 

2. The roots. — Are they numerous or few ? What 
is their color ? Are they rigid or flexible ? Do 
they interlace in a mass or spread out ? Do 
they branch ? If so, are the branches given off 
in definite order ? What is the average length 
of a root ? Diameter ? Cut a large root in two 
and examine the cut end. Is the root made up 
of tissues visible without using a microscope \ 
If so, how do you distinguish them? Is the 
surface of the roots smooth ? Examine one of 
the smallest roots with a lens. Notice the fine 
root hairs. Do they grow at the extreme 
end of the root ? If not, how far from the end 
do they stop \ Note the white growing end. 



324 THE BIOLOGY OF THE PLANT 

How long is it % At the tip look for the brown- 
ish root-cap. How does it compare in length 
with the growing end ? Judging from the facts 
just learned, what do you consider to be the 
principal differences between a ropt and a rhi- 
zome ? 
Make a drawing of a single large root. 

3. The fronds. — How many does your specimen 
bear ? To what extent do they vary in length ? 
Lay an entire frond on a flat surface. What is 
the shape of the outline ? What is the shape 
of the rachis? Color? Size? Is its surface 
rough or smooth ? Does the rachis branch ? 
How many pinna3 does it bear ? Is the num- 
ber constant ? What is their position with re- 
gard to one another ? How far above the sur- 
face of the soil is the first pinna borne ? What 
is the shape of a single pinna ? Size ? Is its 
surface smooth? Compare with the rachis. 
What variations in shape and size do you find ? 
How are the pinnules arranged ? Do they vary 
at all in number, shape, and size on different 
pinnae ? Note the midribs of the pinnae. Do 
the pinnules also have midribs ? If so, what is 
their relation to those of the pinnae ? On which 
side of the pinnules are the sori borne ? Is this 
an invariable position ? Do they have a defi- 
nite arrangement ? If so, what is it ? Does 
each pinnule have a constant number of sori? 
Examine a number of fronds to find sori in 
various stages of growth. What is the first in- 
dication that a sorus is to be formed at a par- 
ticular place ? What changes take place in it 
during its development? What is the shape 



FEEN 325 

of the inclusium ? Size ? How is it attached ? 
What changes take place in it as it de- 
velops? Draw a single pinna, showing both 
surfaces. 

Look for young fronds and notice the manner 
(circinate) in which they are rolled up in the bud. 

Microscopic /Structure. 

a. The rhizome. — Cut a series of transverse sections 
of the rhizome, mount the thinnest and most per- 
fect in a drop of water or dilute glycerine, and 
examine under the low power. Make out the fol- 
lowing parts : on the surface a single layer of 
cells, the epidermis ; within this a band of dark- 
brown cells, sclerenehyma ; enclosed by the 
band of sclerenehyma, a ground mass of light-col- 
ored cells, parenchyma; embedded in the par- 
enchyma, isolated groups of sclerenchymatous 
tissue and large masses of yellowish tissue, the 
nbro-vascular bundles. 
Make a diagram showing the position of all these 
parts. Put on the high power and study each of these 
in detail. 

1. The epidermis.— How many cells in thickness 
is it ? What is the shape of the cells ? What 
do they contain ? How do the different Avails 
of an individual epidermal cell compare in 
thickness? Examine sections in which the 
margin is perfect, and note whether or not the 
epidermis is always present. Does the epider- 
mis present any outgrowths? If so, what are 
they? Is the epidermis broken at places to 
allow of the passage of outgrowths from under- 
lying tissues ? Draw a portion of the epidermis. 



326 THE BIOLOGY OF THE PLANT 

2. The sclerenchyma. — How do you distinguish 

it from the epidermis ? What is the color of 
its cell -walls? What are its cell contents? 
Are the walls stratified, pitted, or marked in 
any way ? Note the line (section of the mid- 
dle lamella) between the adjacent cell- walls. 
Are there any intercellular contents? Does the 
peripheral sclerenchyma pass entirely around 
the stem ? Examine the groups of central 
sclerenchyma. How many are there ? Of what 
are they composed ? Are the component parts 
different from those of the peripheral scleren- 
chyma ? Draw some of the sclerenchyma. 

3. The parenchyma. — Is this sharply marked off 

from the sclerenchyma ? How do its cells com- 
pare in shape, size, color, and contents with 
those of the sclerenchyma? Compare them 
with the parenchyma cells seen in Marchantia. 
Make drawings of the parenchyma. 

4. The fibro-vascular bundles. — Are they visi- 

ble to the unaided eye? How many do you 
find ? Are they arranged in definite positions? 
What is their shape? Are they sharply sepa- 
rated from the surrounding tissues ? JSTote that 
each bundle consists of a group of large, thick- 
walled, empty cells, the xylem portion of the 
bundle, surrounded by a band, the phloem por- 
tion, of smaller, thinner- walled cells, with gran- 
ular contents. Outside of this is a narrow band, 
the bundle-sheath, of cells, next which comes 
the parencl^ma. As sections of the rachis are 
much more easily cut than of the rhizome, the 
detailed examination of the fibro-vascular bun- 
dle will be made when the leaf is studied. Stain 



FERN 327 

a section with Schulze's solution, and note espe- 
cially the color assumed by the cell-walls and 
cell contents of the different tissues. The cell- 
walls which stain yellow are lignified. Stain 
another section with acetic acid carmine, and 
a third with an aqueous solution of haematoxy- 
lin. Compare results. Make longitudinal sec- 
tions. Under the low power note especially the 
course of the fibro- vascular bundles where they 
branch to enter the appendages of the rhizome ; 
also the course of the strands of central scleren- 
chyma. Examine under the high power, and 
note again the shape of the cells of the various 
tissues. Examine in the vascular bundles the 
long, thick-walled elements, the scalariform 
tracheides, marked with narrow parallel pits. 
Stain these sections as above and compare with 
the transverse sections. Draw. 

Carefully remove the bases of the fronds cov- 
ering the extreme apex of the rhizome, and with 
a lens examine the extreme papilla-like end, the 
apical cone or growing point. Make longi- 
tudinal and transverse sections of the growing 
point of two or more rhizomes, and look for the 
triangular apical cells. Study the relation of 
the apical cell to the surrounding cells. 

Cut thick sections of the rhizome, mount them 
on a slide in a few drops of Schulze's macerat- 
ing mixture, and warm the slide over an alcohol 
lamp. After a few minutes the section will be 
resolved into its constituent cells, which may 
then be studied separately. Note particularly 
the shape and markings of the various elements. 
Draw. 



328 THE BIOLOGY OF THE PLANT 

h. The root. — Make transverse sections of a large 
root and examine with the low power. What is 
the outline of the section? "What is its color? 
Do you find the tissues arranged in the same man- 
ner as in the rhizome ? If not, what are the dif- 
ferences ? How many vascular bundles are pres- 
ent ? Notice the root-hairs. Examine with the 
high power. What tissues are lacking ? Do you 
find that the vascular bundles of the roots have 
the same general structure as those of the rhizome ? 
Have they the same shape ? Make a diagram of 
the arrangement of the tissues as seen in this sec- 
tion. What is the shape of the root-hairs ? What 
is their color ? From what tissue do they grow ? 
What is their structure ? Contents ? Compare 
those found on a large root with those near the 
tip of one of the smallest rootlets. What differ- 
ences do you discover ? Draw several root-hairs. 
Examine a section showing a surface view of the 
epidermis, and note the shape and arrangement of 
the cells and of the root-hairs. Draw. 

Study longitudinal sections and compare them 
with the transverse and with longitudinal sections 
of the rhizome. Note particularly the arrange- 
ment of tissues at the places where rootlets are 
given off. Draw. 

Cut off the tip of a young root about a half- 
inch from the end, hold it between two pieces of 
pith, and cut it into very thin longitudinal sec- 
tions. Examine these under the low power for the 
section which passes through the middle of the 
root and contains the apical cell, which lies a 
short distance back from the extreme tip of the 
root. Mount this section in a drop of dilute glyc- 



c. 



FERN 329 

erine and study under the high power. Note that 
the tip of the root is covered by a mass of cells 
forming the root-cap. What is its shape as seen 
in section ? Of what kind of cells is it composed ? 
What is the shape of the apical cell ? How do you 
distinguish it from the surrounding cells? How 
many cells is it from the tip of the growing por- 
tion ? Note the segmental cells. Stain with 
acetic acid carmine. Try to see that some of the 
segmental cells go to form the growing portion of 
the root-cap, while others are added to the root 
itself. From what part of the apical cell does 
each arise ? Study the arrangement of the tissue, 
the meristem, around the apical cell, and note 
the differentiation that is gradually taking place. 
Make drawings to illustrate the structure of the 
tip of the root. Make transverse sections of 
the root-tip and compare. Draw. Compare the 
structure of the root-tip with that of the apex 
of the rhizome. 

The fronds. 

1. The rachis. — Make transverse and longitudinal 
sections of the rachis midway between the low- 
est pinnae and the ground, and examine under 
the low power. What is the shape of the sec- 
tion ? What is its color ? Is the arrangement 
of the parts like that in the rhizome or that in 
the root ? Note the trichomes or hairs around 
the margin of the section. Put on the high pow- 
er. Do you find the same tissues present as in 
the rhizome ? What parts of the section contain 
chlorophyll ? Study the epidermis and compare 
with that of the rhizome. Do the trichomes 
originate in the same manner as the root-hairs ? 



330 THE BIOLOGY OF THE PLANT 

Do they resemble the latter in structure ? Is the 
sclerenchyma arranged as in the rhizome ? Do 
the sclerenchymatous elements have the same 
shape, size, contents, etc., as in the latter? Com- 
pare the parenchyma in the two parts. Study 
carefully the fibro- vascular bundle. Note 
the position and shape. Study the bundle- 
sheath. Of what kind of cells is it composed ? 
Of how many layers of cells is it formed ? What 
is the structure of their walls ? What do the 
cells contain ? Do you find intercellular spaces 
present? Within the bundle-sheath find the 
phloem-sheath, consisting of parenchymatous 
cells containing starch. What is the shape of 
this sheath ? Does it everywhere have the same 
thickness? Do the cells contain protoplasm? 
Inside the phloem-sheath comes the bast or 
phloem, the outer portion of which consists 
of thick-walled elements, the protophloem. 
What is the shape of the cavities in this layer ? 
Are there any intercellular spaces ? Next with- 
in this comes the true phloem, consisting partly 
of elongated, thin- walled elements, the sieve- 
tubes, and partly of parenchymatous cells, the 
bast parenchyma. How many rows of sieve- 
tubes are there ? What is their shape in cross- 
section ? What do they contain ? What is their 
position in regard to the bast parenchyma ? The 
centre of the bundle is occupied by the xylem 
or wood, consisting mainly of thick-walled ele- 
ments. Note the polygonal shape of some of 
the xylem elements, the tracheids, when seen 
in cross-section. How are these elements ar- 
ranged with regard to one another? What do 



FERN 33 1 

they contain ? In longitudinal section they ap- 
pear as the scalariform tracheides already no- 
ticed. Among the elements of the xylem look 
for parenchymatous cells, the wood paren- 
chyma. How do you recognize them ? What 
is their position ? What do they contain? How 
do they differ from the bast parenchyma ? Draw 
a fibro-vascular bundle as seen in cross and in 
longitudinal section. 

Stain the sections with Schulze's solution, and 
note carefully the color assumed by the various 
elements of the bundle. 

Examine sections of the rachis made at points 
where pinnse are given off and others made near 
the upper end of the frond, and compare with 
those from the lower portion. Note the differ- 
ences in the sections and the changes due to 
age. Study also sections made near the junction 
of the rachis with the rhizome. 
Draw the various structures observed in all of these 
sections. 

2. The pinna. — Mount a piece of one of the pinnules 
which bears no sori, and examine both surfaces 
under the low power. What is the nature of 
the surfaces? Are both alike? Of the mar- 
gin? Do you find any veins or fibro-vascular 
bundles which are not visible to the naked 
eye ? Does the green tissue, the mesophyll, 
extend to the extreme margin of the pinnule? 
Cut horizontal sections parallel to the surface 
on each side of the pinnule, thus removing the 
epidermis, and examine with the high power. 
What is the shape, as seen in surface view, of 
the epidermal cells covering the mesophyll ? 



332 THE BIOLOGY OF THE PLANT 

Of those covering the veins ? Study the tri- 
chomes. What is their shape ? Structure ? Do 
they originate from particular cells ? How do 
they compare with the root-hairs and with 
those found on the rachis ? Look for stomata 
surrounded by two kidney-shaped guard-cells. 
Do you find them on both surfaces? Are 
they abundant or few ? What do the guard- 
cells contain ? Do the epidermal cells have the 
same contents ? Compare them with those seen 
in Marchantia. 

Make drawings showing the arrangement of 
the cells of the epidermis. Study transverse 
and longitudinal sections of the pinnule. Does 
it vary in thickness? Note the structure and 
arrangement of the epidermal cells. Do they 
contain chlorophyll ? How many layers in thick- 
ness is the mesophyll ? Notice the arrangement 
of the fibro-vascular bundles. Draw a cross-sec- 
tion as seen under the high power. Mount with- 
out the drop of water and cover-glass a portion 
of a pinnule bearing mature (brown) sori, and 
with the low power examine its under surface. 
Note the indusium covering clark-brown or 
black bodies, sporangia. What is the shape 
of the indusium ? Color ? Does it entirely cover 
the sporangia ? Does it bear trichomes ? Does 
it differ in this respect from the epidermis? 
With a dissecting-needle remove an indusium 
to the slide and mount in a drop of fifty per cent, 
alcohol. Expel the air, then examine under a 
high power. What is the structure of the in- 
dusium ? Do its cells resemble those of the 
epidermis ? Does it have stomata ? In the same 



FERN 333 

manner study young sori. Examine some of the 
mature sporangia in a drop of water. Notice 
that each consists of a stalk, which bears the 
capsule, within which are the spores. What 
is the structure of the stalk ? Of how many 
rows of cells does it consist ? What is the struct- 
ure of their walls? What do they contain? 
What is the shape of the capsule ? Note the 
marginal cells forming the annulus. What is 
their shape ? Color ? Notice particularly their 
arrangement and the structure of their walls. 
Look for sporangia which have broken open 
along the line of dehiscence. Where is this 
line ? If no such sporangia are found, crush 
some by pressing on the cover-glass, or run a 
drop of glycerine under the cover-glass. Draw 
closed and open sporangia. 

How many spores does a sporangium contain ? 
How are they arranged? Examine a single 
spore and note its shape, size, color, structure, 
contents, etc. Draw several spores. Examine 
sections made through pinnules bearing ma- 
ture and those bearing young sporangia. En- 
deavor to make out how the sporangia are at- 
tached in the sorus, how they develop, and how 
the spores are formed within the capsule. Are 
all the sporangia in one sorus of the same age ? 
Can you trace any structural relationship be- 
tween the sporangia and the trichomes ? Note 
also the structure of the indusium. 
Make drawings of each structure examined. 

B. — The Prothallium or Sexual Generation. 

Procure prothallia from the greenhouse, or 



334 THE BIOLOGY OF THE PLANT 

raise them in the manner to be described here- 
after. Place a young prothallium in a drop of 
water and examine under the low power. What 
is the shape of the prothallium ? Color ? Look 
for rhizoids on the lower surface. Are they con- 
fined to any particular region ? Draw. Examine 
with the high power. What are the general char- 
acters of the cells composing the prothallium? 
What do they contain ? Look for the growing 
point at the base of the depression in the margin. 
How do the rhizoids differ from the root-hairs on 
the fern-plant ? From the rhizoids of Marchantia ? 
Among the rhizoids look for knob-like bodies, the 
antheridia and the archegonia. The former 
may be distinguished in surface view as consisting 
of a small circular eminence of a single large cell, 
or of several small ones without any opening be- 
tween them ; each archegonium usually appears as 
a ring of four cells surrounding a plainly visible 
opening, the mouth of the canal. What other dif- 
ferences can you distinguish between these two or- 
gans? In case mature specimens are examined, 
many antherozoids will probably be found swim- 
ming around in the water. If so, study their move- 
ments and structure. Note the body of the an- 
therozoid and the cilia. To what part of the 
body are the latter attached ? Are they numerous 
or few ? Look for the vesicle, which is usually 
attached to the body. Draw several anthero- 
zoids. To make out the structure of the arche- 
gonium, sections of the prothallium should be cut. 
Successful sections will show an archegonium to 
consist of a neck — down which runs a canal, 
whose mouth was seen in the surface view — 



FEEN 335 

and a body, in which may be distinguished an 
oosphere. Study the structure of these parts 
and compare with the corresponding parts of 
Marchantia. Draw. 

PHYSIOLOGY 

a. The germination of the spore and the development of 
the jprothallium. 

Sow a few spores in a drop of water in a moist 
chamber. How long before the spore ruptures? 
What changes take place in it at this time ? What 
is the shape of the embryo prothallium? How 
long before the primary root-hairs develop? Only 
the first stages can be observed in water cultures. 
To get the later developmental stages, spores may 
be sown on slabs of plaster of Paris, pieces of 
porous earthenware, or, best of all, on clean, damp 
sand. The cultures must be kept damp and be 
examined every few days. On older prothallia, 
look for the first rudiments of the asexual gen- 
eration (the fern-plant proper), which in sections 
will be seen issuing from an archegonium which 
has been fertilized. Still later stages will show 
a single leaf borne above the prothallium, and 
from this point the development may be watched 
with the naked eye. 



The Flowering Plant 

A. — Seeds 

Material. — Select a number of well-formed dry seeds, 
including beans, peas, corn, cucumber, watermelon, oak, 
maple, flax, and mustard. 

Other material and apparatus required : an egg, corn- 
starch, iodine, barium hydrate, sodium hydrate, one per 
cent, solution of copper sulphate, grape-sugar, distilled 
water, Millon's reagent, diastase of malt, a few test- 
tubes, parchment, gauze, blotting-paper, filter -paper, 
bell-jar, tumbler, razor, cork, scalpel, small funnel, alco- 
hol lamp, forceps, dividers, metric scale, hand-lens, 
chemical thermometer, compound microscope, dialyzers, 
and a piece of glass tubing four inches long and two 
inches in diameter. 

MOEPHOLOGY 

Soak a number of large seeds — e. g., beans, peas, corn, 
etc. — in water overnight in order to soften them. 

I. — Bean, notice : 

a. /Shape. — What is the shape of the bean as viewed 
from the side ? From the edge ? From the end % 
Compare several different kinds to see the varia- 
tions in shape. How do you account for the 
shape ? 



THE FLOWERING PLANT — SEEDS 337 

h. Size.— What is the length ? Breadth ? Thickness? 
Measure several carefully. What variations in 
size ? 

c. Color. — What is it? What variations? Is the 

color in the covering or in the fleshy portion? 
Of what use is the color? What is the cause 
of it? 

d. Structure. 

1. The seed-coat or testa. — What is its structure ? 

Color? Use? 

2. The hilum, or scar left by the seed-stalk or funi- 

culus. — What is its position? Shape? Size? 
Use? 

Near the hilum find 

3. The micropyle. — Examine several seeds to see 

if its position is constant. What is its shape ? 
Size? Use? 
Tear away the testa and note 

4. The cotyledons. — How many are there ? What 

is their position ? Shape ? Color ? What re- 
lations do they bear to the embryo as regards 
position and size ? 

5. The embryo, consisting of caulicle and plu- 

mule. — What is its shape ? Is it attached to 
the cotyledons ? If so, how ? How do you 
distinguish the caulicle from the plumule ? In 
what direction does the tip of the caulicle 
point? Examine several beans to see if it al- 
ways points in this direction. What is the posi- 
tion of the tip of the caulicle with relation to the 
micropyle ? What is the structure of the cauli- 
cle ? Shape? Size? What is the position of the 
plumule? Of what is it composed? Compare 
22 



338 THE BIOLOGY OF THE PLANT 

it in shape, size, and structure with the cau- 
licle. 
Make sketches of the bean, illustrating all of these 
structures. 

IT. — Examine in like manner seeds of the watermelon, 

cucumber, pea, oak, maple, and corn. Compare 

them with the bean in all respects and explain 

the differences. 

Draw each kind of seed examined to show its structure. 

What are the structural differences between a seed 

and a spore? 

III. — Some of the Chemical Contents of Dry Seeds. 

a. Tests for starch. 

1. Fill a test-tube one -third full of water, add a 

pinch of dry corn-starch, and shake the tube. 
Does the starch dissolve? Heat the tube to 
the boiling-point over the flame of an alcohol 
lamp, keeping the tube agitated during the 
process to keep the starch from settling to the 
bottom of the tube. What change takes place ? 
Explain. Set the tube aside to let the starch 
cool. 

2. Fill another tube one -third full of water, and 

add a drop of iodine. What result ? Explain. 

3. Add a drop of iodine to the cold starch in the 

first test-tube and shake the tube. What re- 
sult ? Compare with 2. To what is the dif- 
ference in results due ? 

4. Peel the testa from several dry beans, break the 

beans into small pieces, place the pieces in a 
test-tube containing water, and boil them for 
several minutes. Then cool the tube and di- 



THE FLOWERING PLANT SEEDS 339 

vide the contents into two parts. Test the first 
part with a drop of iodine. Does the bean con- 
tain starch ? How do you tell ? Filter the sec- 
ond part until perfectly clear, and test the fil- 
tered fluid with iodine. Is starch present? 
Does starch dissolve when boiled ? 
5. Test the testa for starch. Does it contain any 
starch? In what part of the seed is starch 
stored ? Put a drop of iodine on the surface 
of an uninjured cotyledon of a soaked bean. 
What result? Explain. Cut the end off the 
cotyledon, and apply a drop of iodine to the 
cut surface. What result? In what part of 
the cotyledon is the starch stored ? 

b. Tests for grape-sugar. 

1. Put some grape-sugar (glucose) into water in a 

test-tube. Does the sugar dissolve? Do you 
think that if a plant-cell contained grape-sugar 
it would be ^dissolved in the watery fluid (cell 
sap) forming the vacuole ? Compare with the 
starch. Test the sugar with iodine. Do you 
get the same reaction as with starch ? Why ? 

2. Fill a test-tube one -fourth full of water, add an 

equal amount of sodium hydrate, and shake 
the tube. What change? Add two or three 
drops of a one per cent, solution of copper sul- 
phate. What change ? Shake the tube vigor- 
ously. What change ? Boil the contents of 
the tube for a minute or two. What change ? 

3. Into a test-tube one -fourth full of water put a 

pinch of grape-sugar, then add the sodium hy- 
drate and copper sulphate as before, and shake 
the tube. Then boil for a minute or two. Do 



340 THE BIOLOGY OF THE PLANT 

you get the same result as you did without the 
grape-sugar ? To what, then, is due the change 
noticed in this last experiment ? 

4. Kepeat the preceding experiment, using starch 

instead of grape-sugar. Do you get the same 
result as with grape-sugar ? Why ? Can you, 
then, by using sodium hydrate and copper sul- 
phate, detect the presence of grape-sugar in a 
solution ? Could you detect it by merely look- 
ing at the solution, i. e., without the use of 
chemicals ? 

5. Prepare some dry beans or corn as previously 

directed. Filter the contents of the test-tube 
used into another tube, add sodium hydrate 
and a few drops of copper sulphate, and boil. 
"What result? Is grape-sugar present in the 
dry seed ? How do you tell ? 

c. Tests for albumen (aleurone). 

1. Into a test-tube about one -third full of water 

put two or three drops of the white of an egg, 
and shake the tube. Pour into the tube ten or 
twelve drops of sodium hydrate. Shake again, 
add one or two drops of a one per cent, solu- 
tion of copper sulphate, shake vigorously to 
mix thoroughly the contents of the tube, then 
boil. If the deep-blue color formed by the 
mixture of the two reagents changes to a pur- 
ple, either before or after boiling, the presence 
of an albuminous substance is indicated. 

2. Repeat the above, using boiled starch in place of 

the white of egg. Do you get the purple color? 
Why? 

3. Prepare some beans free from the testa, as was 



THE FLOWERING PLANT — SEEDS 341 

done for the starch tests, boil the pieces in 
water for a few minutes, then pour into the 
test-tube ten or twelve drops of sodium hy- 
drate and one or two of the copper sulphate, 
and boil again. Does the color indicate the 
presence of an albuminous substance ? 
4. Repeat the last experiment, using a few drops 
of Millon's reagent in place of the other two 
chemicals. If the contents of the test-tube turn 
pink or red the presence of an albuminous sub- 
stance is indicated. 

IV. — Microscopic Examination of Starch and Aleurone. 
Mix a pinch of starch and some water together in a 
watch-glass, then put a drop of the mixture un- 
der the microscope, and note the shape, size, col- 
or, and structure of the starch grains. Carefully 
run a drop of iodine under the cover-glass, and 
note the effect on the starch. With a sharp ra- 
zor cut a very thin section across a softened cotyl- 
edon of a bean, examine the section under the 
microscope, and note how the starch is stored 
away in the cells. Does this give you any clue 
to the explanation of the results obtained in 5 
under " Tests for starch" ? Test the section with 
iodine. Note the very small aleurone grains in 
the starch-bearing cells. What color do they as- 
sume when stained with iodine ? Note the aleu- 
rone grains stored in the cells near the surface of 
the cotyledon. Draw. 

Focus upon the surface of a cell-wall, and no- 
tice the small circular openings, the ends of 
canals, which perforate the wall. Focus upon 
the edge of a wall between two cells, and note 



,342 THE BIOLOGY OF THE PLANT 

the length of these canals. Compare the diame- 
ter of the canals with that of a starch grain. Are 
the canals large enough to admit of a starch 
grain passing through them from one cell into 
the next? Can, then, the starch grains be car- 
ried into and out of the cells by the flow of sap 
through the tissues of the cotyledon ? 

Compare the results of all your experiments 
on the dry seeds. Do you find starch present ? 
Grape-sugar? Aleurone? In what form does 
each of these exist in the seed ? 

PHYSIOLOGY 

a. Imbibition and turgescence. 

1. "With a pair of dividers measure the length, 

width, and thickness of several dry beans, then 
put them into a dish of water, and examine at 
intervals of three to five minutes. Explain the 
changes which take place. Let the beans re- 
main in the water overnight. What change ? 
Explain. Compare the measurements of the 
soaked with those of the dry beans. Is the 
average increase in the size of the beans due 
to the imbibition of water? Let the beans 
dry in the air. Do they regain their original 
size? 

2. Pack a thin glass bottle full of dry beans, pour 

in enough water to cover them, fasten the stop- 
per tightly with a cord or wire, set the bottle 
aside for a few hours, then examine. Explain 
the result. Do seeds imbibe water in spite of 
great external pressure ? Compare the behavior 
of the seeds in this experiment with that of a 



THE FLOWERING PLANT — SEEDS 343 

sponge immersed in water, but held tightly 
squeezed in the hand. 
3. Provide a glass tube about four inches long and 
two inches in diameter and open at each end, 
two pieces of thin parchment well soaked in 
water and sufficiently large to tie over the ends 
of the tube, about two table-spoonfuls of syrup 
(or, better, the same amount of grape-sugar or 
glucose), a piece of strong twine, and a dish 
holding about a pint of distilled water. Over 
one end of the tube tie a piece of the moistened 
parchment so tightly that it cannot slip off, but 
leave that part of it which covers the calibre of 
the tube somewhat loosely wrinkled or plaited. 
Pour in the syrup, diluted with sufficient water 
to fill the tube, or put in the dry grape-sugar, 
and fill the tube with water. Tie over the open 
end the second piece of moistened parchment, 
arranged like the first. Turn the tube first on 
one end, then on the other, to see that none of 
the syrupy fluid within can come out, then place 
it in the dish of distilled water. Examine the 
tube from time to time to see whether or not 
the parchment is become tense and outwardly 
convex. What makes the parchment bulge? 
Are the conditions of the experiment at all 
similar to those of a plant-cell — e. g., one of the 
cells of Spirogyra — immersed in water ? Com- 
pare the end walls of the tube with the ends of 
a filament of Spirogyra. If a plant-cell whose 
walls were more or less flaccid, and whose con- 
tents were a fluid — i. e., cell-sap— denser than 
water, be placed in the latter, would the cell 
absorb some of it ? Would the walls become 



344 THE BIOLOGY OF THE PLANT 

tense and stretched, i. e., turgid ? What changes 
would take place in a tissue composed of such 
cells ? 

h. Germination. 

Sow some beans, corn, and pumpkin seeds in 
damp sawdust or sand, and put some flax and 
mustard seeds on damp blotting-paper under a 
bell-jar. Examine from day to day, and note the 
changes which take place. What is the first visi- 
ble sign that germination has begun ? On which 
day does the radicle appear? On which the co- 
tyledons and caulicle ? What becomes of the 
seed-coats ? Note the behavior of the cotyledons 
— how they are withdrawn from the seed-coats 
and from the soil, how they expand or unfold, 
and the changes which take place in the shape, 
size, and color of the cotyledons as growth goes 
on. When do the first true leaves unfold ? When 
does the second pair appear ? In which direction 
does the primary root grow ? Examine the roots 
for root-hairs. Where do they first appear ? Do 
they grow at the extreme tip of the root ? Ex- 
amine with a microscope the hairs on a root 
which is two or three inches long. How do the 
hairs on the lower differ from those on the upper 
end ? How do you explain the difference ? Sow 
some mustard seeds in loose, damp sand. After 
they have germinated, carefully draw them out 
of the sand along with the particles attached to 
the root-hairs. Wash gently in water to get rid 
of the unattached particles. Do you find that 
much of the sand adheres to the root -hairs? 
What do you consider to be the function of these 



THE FLOWERING PLANT SEEDS 345 

hairs? Compare with those seen on the fern 
roots. 

Allow some seeds to germinate in the light, 
others of the same kind in the dark. Explain the 
differences. 

Look under the trees for germinating acorns, 
horse-chestnuts, maple, and pine seeds, and en- 
deavor to explain the various peculiarities found. 

Do the cotyledons of any of the seeds contain 
chlorophyll before germination ? After ? Do 
those with chlorophyll have thick or thin cotyle- 
dons ? Can you give reasons ? 

Fill a tumbler about half full of water, tie loose- 
ly over the mouth of the tumbler a piece of gauze, 
allowing it to hang down into the tumbler, but 
not to come in contact with the water. On the 
gauze place a few flax seeds, grains of wheat, 
oats, etc., cover the whole with a bell- jar, and 
set in a warm place near a window. Do the 
seeds germinate? If so, do they germinate as 
quickly as those placed on blotting - paper or 
damp sand? Whence do they get the moisture 
needed for germination? Judging from this ex- 
periment, would you regard seeds as having a 
very strong tendency to absorb moisture from the 
soil, although there might be but little moisture 
present ? How does this agree with facts ob- 
served in the garden and in the field ? 

c. Geotrqpism of seedlings. 

Pin a germinating bean or kernel of corn to a 
flat piece of cork, with the bean upon the upper 
surface, and with the radicle pointing upward and 
the caulicle downward. Float the cork in some 



346 THE BIOLOGY OF THE PLANT 

water in a dish ; cover the dish with a bell-jar 
or tumbler in order to prevent evaporation, and 
study the behavior of the radicle and caulicle. 
Explain. 
Make drawings illustrating the facts observed. 

d. Respiration. 

Allow some beans or peas to germinate in a 
corked bottle with a wide mouth. When they 
are well started, pour some barium hydrate into 
a watch-glass, invert the bottle over the glass, 
and carefully withdraw the cork, holding the 
mouth of the bottle close to the surface of the 
liquid. What change in the liquid % Explain. 

e. Temperature of germinating seeds. 

Put some germinating seeds into a beaker under 
a bell-jar having an open top. Close the top with 
a stopper having two openings, into each of which 
is thrust a chemical thermometer. Push one ther- 
mometer down until its bulb is buried among the 
seeds. After a few hours take the readings of 
the thermometers. Explain. 

f. Some of the chemical contents of germinating seeds. 

Take a number of germinating seeds, e. g., corn, 
which are just beginning to develop roots and 
stems, with a knife cut the seeds into small pieces, 
boil them for a few minutes in a test-tube, and 
divide the contents of the tube into three parts. 
Test one part with iodine for starch. Do you find 
it present? Test the second part with sodium 
hydrate and copper sulphate for glucose. Is it 
present ? Test the third portion for the presence 
of proteids with Millon's reagent. Do you find 



THE FLOWERING PLANT SEEDS 347 

any proteid substances ? Compare the chemical 
contents of germinating with those of dry seeds. 
Do you find anything present in the germinating 
which is not in the dry seed? Bake some dry 
seeds to destroy their power of germination, then 
place them in water. Do they still absorb water ? 
If so, test some of them for starch and others for 
glucose. Is the formation of glucose in a germi- 
nating seed due to some chemical change which 
takes place as the seed germinates, or to the im- 
bibition of water? Why? 

g. Action of the diastase of malt upon starch. 

Make a thin starch paste by adding to boiling 
water a few drops of a mixture of dry starch and 
water. Cool the paste, and to it add a pinch of 
Merck's diastase of malt, which may be obtained 
of druggists. Let the test-tube stand in a warm 
place for a few minutes, then test its contents for 
the presence of glucose. Do you find any ? Can 
diastase change starch to grape-sugar? If a di- 
astasic ferment were present in a plant -cell, do 
you think that the starch in the cell might be 
changed to glucose ? 

h. Osmosis. 

Take two dialyzers. Into the inner jar of one 
put some starch mixed with water ; into the in- 
ner jar of the other put some grape-sugar dis- 
solved in water. Into the outer jar of each put 
distilled water. After a few hours test the water 
in the outer jar of the first dialyzer for starch ; 
that in the outer jar of the second for grape- 
sugar. Which dialyzes ? 
Keview the experiments on the contents of 



348 THE BIOLOGY OF THE PLANT 

dry and of germinating seeds. Can you trace 
any connection between this experiment and the 
transfer of food-material from the storage leaves 
or cotyledons into the growing parts of the seed- 
ling plant ? 

Make sections of a cotyledon of a bean plant 
which has developed two or three pairs of leaves. 
Do you find as much starch present as before 
germination ? Explain. 

B. — Stems 

Material. — Provide as specimens of the woody plants 
stems about two feet long of the horse-chestnut, elm, 
maple, willow, cherry, and pine. These should be 
taken during the winter or before the leaves expand in 
the spring. If to be examined during the early summer 
they may be preserved by being placed for a day in fif- 
ty per cent., and then kept permanently in eighty per 
cent, alcohol. To compare with these have fresh or al- 
coholic material bearing the expanded leaves and the 
flowers. It is possible to use dried specimens, but only 
as a last resort. For herbaceous stems use the Bego- 
nia or Geranium, Tradeseantia (Wandering Jew), and 
strawberry, all of which may be had in the garden at 
certain seasons or at the greenhouse at any time of 
year. Have also a metric scale, dividers or calipers, 
forceps, hand-lens, razor, compound microscope, Schulze's 
solution, iodine, acetic acid carmine, Schulze's macerat- 
ing mixture, acetic acid, hydrochloric acid, phloroglu- 
cin, sponge, bell-jar, small camel's-hair brush, India ink, 
and scalpel. 

Method of Examination. — First study the arrange- 



THE FLO WEEING PLANT — STEMS 349 

ment and shape of the branches on the plant. Remove 
some to the laboratory, and study their structure as de- 
tailed below. When not in use keep the material, if 
fresh, under large bell -jars or in closed boxes, with 
plenty of moisture and protected from evaporation. 
Examine alcoholic material in a mixture of equal parts 
of glycerine and fifty per cent, alcohol. 

MOEPHOLOGT 

Naked-eye Characters. 

Examine the stem of the horse-chestnut, and 
note the following characters : 

a. Shape. — What is it? What variations do you find 
in different specimens ? Is there a general shape 
for all of the branches on the tree ? How does 
the shape of the branch compare with that of the 
main stem or trunk of the tree? How do you 
account for the bends in the stem ? Draw. 

h. Size. — What is the diameter of the specimen under 
examination? Is it the same throughout its 
whole length? How do you account for the 
facts observed ? 

c. Color. — What is the general color of the branch ? 

To what is it due ? Do you find any variations in 
color in different parts of the stem ? How do you, 
account for such ? 

d. Structure. — Notice that the stem consists of a se- 

ries of sections or internodes connecting at 

joints or nodes. 
1. The internode.— What is the shape of an inter 
node ? The average length ? Does the length 
vary in different parts of the stem ? How do 



350 THE BIOLOGY OF THE PLANT 

you account for the results obtained? How 
much does the stem grow in length in one 
year ? Is the growth even ? How many inter- 
nodes are there on the specimen examined? 
Notice the leaf-scars. Where are they found? 
How do you distinguish them from other parts 
of the stem ? What is their position with refer- 
ence to one another ? Are all at the same dis- 
tance apart ? What is their shape ? Examine 
the small points, the ends of the fibro- vascular 
bundles of the leaf, found in each scar. How 
many are there? Is the number constant? 
How are they arranged? What relation do 
the leaf-scars bear to the buds ? 

Examine the bark on an internode. Note 
its color and thickness. Notice the breaks in 
it on the lower internodes. Do you find them 
also on the upper ones? Why? In what di- 
rection do these breaks run ? How do you ac- 
count for them ? Examine the small, wart-like 
points, the lenticels, on the bark. Do they 
have any regular arrangement? How many 
are there on an internode ? Carefully peel off 
the bark to see whether the lenticels originate 
in the bark itself or in the tissues below. With 
a sharp knife or scalpel cut crosswise through 
the middle of the first internode of the stem ; 
make also a longitudinal section through the 
middle of the internode, and note that the 
stem consists of the following layers, named in 
order from the outside towards the centre. 
2. The brown bark. — In addition to the features 
already observed, note its thickness as com- 
pared with the other layers. Do you find any 



THE FLOWERING PLANT — STEMS 351 

decided variation in thickness % Does the bark 
completely cover the stem? From its charac- 
ters would you judge it to be a living tissue ? 
Hold a piece of bark up to the light to see if 
the bark is transparent. Examine bark from 
different parts of the stem with regard to this 
point. What do you consider to be the func- 
tion of this layer ? 

3. The green bark. — How does it compare in 

thickness and texture with the outer bark? 
To what is its color probably due ? Of what 
use may this layer be in this part of the 
plant ? 

4. The bast. — What is its color? How does it 

compare in thickness with the other layers ? In 
what direction do its fibres run ? Do you find 
indications of more than one layer ? Of what 
use is the bast ? 

5. The wood. — How does it compare in color, text- 

ure, and thickness with the other layers ? Ex- 
amine under a lens to see the annual rings 
and the medullary rays. How many rings 
do you find ? Are all of the same width ? Why ? 
How much does the stem increase in diameter 
in one year? Make cross sections of other in- 
ternodes of the same stem, and note the num- 
ber of rings found in each. Is it the same for 
all ? How do you account for the results ? In 
what direction do the medullary rays run? 
With what parts do they connect? Of what 
use to the stem is the wood ? Note how easily 
the bast separates from the wood. 

6. The pith. — How much of the cross-section does 

it occupy ? What is its texture ? Does the pith 



352 THE BIOLOGY OF THE PLANT 

extend through the entire stem ? In what part 
of the stem is the pith relatively greatest in 
amount ? Of what use is it ? 
Make drawings of cross and longitudinal sections of 
the internode, showing the disposition of the tissues. 
7. The node. — How is it formed? How do you 
distinguish it from the internode? How does 
it compare in length with the internode? Is 
the arrangement of tissues in the node the 
same as in the internode ? What relation does 
the node bear to the leaf-scars ? To the buds ? 
To the side branches ? 
Examine and compare with the horse-chestnut stem 
stems taken from the elm, maple, willow, cherry, and 
pine, and make drawings showing the structures ob- 
served. Study the stems of herbaceous plants like the 
Begonia, Tradescantia, strawberry, etc. Make draw- 
ings of these stems. 

Microscopic Structure. 

Make cross-sections of the last internode of a 
branch of the horse-chestnut taken in the winter, 
mount some of the best in water or dilute glyce- 
rine, and study under the low power. Note the 
general arrangement of the tissues seen in the 
cross-section in the study of the gross anatomy 
of the stem — the brown bark or cork, enclos- 
ing a chlorophyll - bearing layer, the cortical 
parenchyma, within which comes a ring of 
thick - walled fibres of sclerenchyma, the bast 
fibres, this being intimately associated with the 
soft bast which shades into a ring of small cells, 
the cambium, with granular contents. Then 
comes the wood or xylem, some of whose ele- 



THE FLOWERING PLANT STEMS 353 

ments show large openings. Note the appear- 
ance of the annual rings. In the centre lies the 
pith or medulla. Make a diagram showing the 
arrangement of all these parts. Put on the high 
power and study the structure of each of these 
tissues. Do you find an epidermis ? If so, does 
it form a continuous layer ? What is the struct- 
ure of its cells ? Contents ? How many cells in 
thickness is the cork -layer? What is their 
shape ? Are there any intercellular spaces ? Do 
these cells have a definite arrangement ? Do the 
walls of these cells vary in thickness ? Compare 
the outer with the inner cork-cells. What do the 
cork-cells contain ? Do you find any places where 
a mass of cork-cells has pushed through the epi- 
dermis and formed a lenticel ? What is the shape 
of the cells of the cortical parenclryma? Com- 
pare their arrangement with that of the cork- 
cells. What contents have these parenchymatous 
cells? Do you find any crystals? If so, test 
them with acetic and hydrochloric acids. Of 
what are the crystals composed? How are the 
bast-fibres arranged? Is the ring of bast-fibres 
broken or continuous? What is their shape? 
Contents? How do you distinguish the soft 
from the hard bast or bast fibres? Note the 
arrangement of the cells of the cambium. Does 
it form a complete ring? What is the shape of 
its cells ? How do their walls compare in thick- 
ness with those of the other cells in the section ? 
Do you find that the cells of the tissues (xylem 
and soft bast) on each side of the cambium have 
the same arrangement as the cells of the latter? 
If so, explain. Note the arrangement of the ele- 
23 



354 THE BIOLOGY OF THE PLANT 

ments of the xylem. Do you find that those with 
large cavities, or vessels, occur in definite places? 
Do you find any elements which run in radial 
lines, the medullary rays, from the pith to the 
cambium ? Can you trace the rays beyond the 
cambium ? What is the shape of the cells forming 
the medullary rays ? Why are these rows of cells 
called " medullary rays " ? 
Draw a portion of the section showing all of the ele- 
ments with their contents. 

Study the shape, arrangement, and contents of 
the cells of the pith. Stain sections in Schulze's 
solution and in phloroglucin. Note particularly 
the color assumed by the elements of each tissue. 
Cut other sections two or three internodes below, 
and compare with those just examined. What 
gives the xylem the appearance of being composed 
of concentric rings, the annual rings ? Do these 
rings vary in thickness as compared with one 
another? If so, to what is the difference due? 
Do different parts of the same ring vary in thick- 
ness ? Why ? Make drawings showing the cause 
of the ringed appearance. Cut other cross-sec- 
tions through the upper and the lower end of 
the green stem of the current year, and com- 
pare with the others. How many fibro-vascular 
bundles can you find in the young stem ? What 
changes take place in their number and position 
in the older stems ? Using the proper reagents, 
especially phloroglucin, try to trace the change of 
the cellulose into the lignified elements of the 
xylem as the stem gets older. Make longitudinal 
sections and compare with the transverse sections. 
Draw. 



THE FLOWERING PLANT STEMS 355 

Isolate the elements of the stem by using 
Schulze's macerating mixture. Draw several of 
each kind of element found. 

Examine transverse and longitudinal sections 

through the growing point or punctum vegeta- 

tionis. Section the other stems, and compare 

with that of the horse-chestnut and with one 

another. Notice particularly the tracheides, 

which form the greater part of the xylem in the 

pine stem. Draw several. Study especially the 

stems of the Begonia and Tradescantia. 

Make drawings of all of the sections studied. "What 

structural resemblances can you trace between any of 

these stems and the rhizome of the fern ? 

PHYSIOLOGY 

a. Movements. 

1. Geotropism. — Sow some seeds, as mustard, flax, 
peas, and beans, in the meshes of a coarse 
sponge, and keep the latter well moistened un- 
der a bell-jar, placed near a window, until the 
seeds germinate and the young stems appear. 
Notice particularly the direction of several of 
the stems of each kind of plant. With a fine 
camel's-hair brush, dipped into India ink, paint 
four lines at equal distances apart, dividing 
each stem into quarters, and running from the 
cotyledons down to the surface of the sponge. 
Turn the sponge upside down, being careful to 
keep the plants in the same position as regards 
light. Examine the plants both morning and 
afternoon for several days. Does the direction 
of the stems change? In what way? How 
soon can you detect, by the bending of the lines 



356 THE BIOLOGY OF THE PLANT 

on the stem, that the latter is moving ? How 
long does it continue ? In what part of the 
stem does the bending begin ? Reverse the 
plants again. Do they again change their 
position ? 

2. Heliotropism. — Prepare another set of plants in 

the same manner. When they have become 
well started, revolve the sponge so as to place 
on the side towards the centre of the room 
those plants which were on the side towards the 
window, and vice versa. Does any change take 
place in the plants? If so, in what direction 
do they move ? Do you find this to be a com- 
mon phenomenon among plants ? 

3. Twining. — Raise some morning-glory plants in 

a flower-pot covered by a bell-jar, and when the 
plants are large enough stick into the soil by 
the side of each a slender stake about a foot 
long. Does the plant make use of the stake as 
a support? How high is the plant before it 
begins to twine ? Do the plants begin to twine 
around the stake without first being put in con- 
tact with it ? What is the first internode which 
begins the process ? Do all of the plants turn 
in the same direction around the support ? 

b. Direct observation of the ascent of water in the stem. 

Select a stem of Tradescantia having several 
long, straight internodes. Hold the stem under 
water, as in a wash-bowl, and with a razor di- 
vide it transversely near the lower end of the 
straight portion, being careful to keep the cut 
portion of the apical end under water. Then, 
still holding the stem under water, cut a piece 



THE FLOWERING PLANT — HOOTS 357 

off each side of the lowest internode, leaving the 
latter in the form of a long, thin wedge, whose 
tip is so thin as to be transparent. With a rub- 
ber band loosely fasten the stem to the surface 
of a slide, remove the preparation from the wa- 
ter, being careful to keep the section well mois- 
tened, wipe the superfluous water off the slide, 
put on the cover-glass, and examine under a me- 
dium power. Find the ends of the spiral vessels 
in the nbro-vascular bundles, and look for small 
particles being carried into the mouths of these 
vessels. If no particles are seen, add a drop of 
water containing a little powdered indigo or car- 
mine. Do the particles enter any other elements 
than the spiral vessels ? How rapid is the flow 
of water into the vessels? With a quick stroke 
of a sharp razor cut off the leaves one by one, 
noting the rate of flow after the removal of each 
leaf. Does their removal have any influence on 
the rate of flow? 

C. — Eoots 

The examination of the gross and microscopic struct- 
ure of these organs and the devising of physiological 
experiments are left to the ingenuity of the student. 
The roots of the flowering plants differ so little from 
those of the fern and from the rhizome of the fern and 
the stems just examined, that the student ought readily 
to comprehend the resemblances and differences. As 
specimens to work upon it is suggested that several of 
the following be used : seedling maple, beet, Indian 
corn, onion, bean, ivy, mustard, oat, and pumpkin. Both 
fresh and alcoholic material should be used. 



358 THE BIOLOGY OF THE PLANT 

Let the student make the examination with a view to 
answering the following questions : What is the general 
structure of roots? What are the most noticeable 
structural differences between roots and stems ? How 
do the vascular bundles of the former compare with 
those of the latter in arrangement and structure ? How 
and where does the transition of root to stem take 
place? In what way and from what tissues do the root- 
hairs originate? How does the root grow in length? 
In thickness ? Are the root-hairs actually attached to 
the particles of the soil in which the plant grows ? In 
connection with this question the following experi- 
ment is suggested : In the bottom of a box about a 
foot square and three inches deep lay a piece of well- 
polished marble. Fill the box with clean, damp sand, 
and in the latter plant beans, peas, wheat, and corn. 
After two or three weeks, by which time the roots will 
have become well grown, empty the box, carefully wash 
the marble, and look for the " corrosion figures " made 
upon its surface by the roots of the seedlings. Can you 
give any explanation of this result ? 

D.— Buds 

Material. — The best material is to be had in spring 
before the buds expand, as then they are largest and 
most easily examined. A series of specimens should be 
made to illustrate the gradual growth of the buds of 
various plants. The collection of these specimens should 
be begun in the early summer, when the young buds of 
next season will be found forming in the axils of the 
leaves of the current year. Beginning with May, col- 
lect each month from the plants named hereafter a set 
of stems bearing thrifty buds. Put the stems for a day 



THE FLOWERING PLANT — BUDS 359 

into a saturated solution of picric acid in water, wash 
the stems for half an hour in thirty per cent, alcohol, 
then place them in fifty per cent, and seventy per cent, 
alcohol, each for a day, and keep permanently in eighty- 
five or ninety per cent, alcohol. 

Provide buds of the horse-chestnut, lilac, hickory, 
tulip-tree, maple, elm, cherry, potato (tuberous portion), 
and onion. 

Use will be made of the scalpel, hand-lens, compound 
microscope, dilute potash, dilute glycerine, Schulze's 
solution, acetic acid carmine, razor, watch-glasses, and 
metric scale. 

Method of Examination. — Study first fresh, fully de- 
veloped buds, then examine the set of preserved speci- 
mens. If these have been kept in strong alcohol, soak 
them for two or three hours in a mixture of three parts 
of fifty per cent, alcohol and one part of glycerine, and 
keep them moistened with this mixture while the ex- 
amination is in progress. Section the buds in various 
directions for the study of both gross and minute 
anatomy. 

MORPHOLOGY 

Naked- eye Characters. 

Examine the buds of the horse-chestnut in 
spring before they begin to swell, and again when 
they are partially expanded. 

a. Position. — At what places on the stem are buds 
formed? Do they occupy a constant position? 
Do you always find buds in this place? What 
determines their position ? How many buds do 
you find on an internocle ? Do they occur singly 
or in pairs ? 



360 THE BIOLOGY OF THE PLANT 

o. Shape. — What is the shape of the bud before it be- 
gins to expand ? How does the shape change as 
expansion goes on ? Of what use may this par- 
ticular shape be ? 

c. Size. — Measure the length and diameter of the bud 

before it swells. As the bud expands, which in- 
creases the more, the length or the diameter? 
Do you find any especially small buds? If so, 
does their position correspond to that of the 
larger buds ? How do you account for the pres- 
ence of the small buds ? 
Draw several of the buds. 

d. Color. — What is the color ? Is the bud evenly col- 

ored ? To what parts of the bud is the color con- 
fined? Of what use is this particular color? 

e. Structure. 

1. The bud- scales. — In what part of the bud are 
they found ? Does this position have any rela- 
tion to that of the leaf -scars on the stem? 
How many scales are there? What is their 
color ? Are they evenly colored ? What vari- 
ations in size, shape, and color? What is the 
texture of the base of the scale ? Of the top ? 
Of the edge ? How does the inner differ from 
the outer surface? Notice the varnish on the 
outside of the bud. Do you find it anywhere 
else than on the scales ? Do you find it on all 
of the scales ? On all parts of the scales ? Of 
what use is it ? Is the scale at all leaf -like in 
structure? In color? In shape? At what 
time of year are the scales formed ? Do they 



THE FLO WEEING PLANT — BUDS 361 

remain after the bud has expanded ? What 
functions do the bud-scales perform ? 
Draw several of the bud-scales. 

2. The young leaves. — In what position do you 

find them? How many are there? Is there 
any correspondence between the position of 
the leaves in the bud and that of the leaf- 
scars ? Spread out one of the leaves. Does it 
resemble in any way the fully developed leaf ? 
In what manner is the leaf folded in the bud, 
or, in other words, what form of vernation 
does it illustrate ? Compare with the fern frond. 
Note the down covering the leaves. Of what 
use is it ? At what time of year are the leaves 
formed ? As the bud expands notice the man- 
ner and order in which the leaves appear. If 
the buds be examined before the leaves unfold, 
their expansion may be hastened by keeping 
the stems bearing the buds in a warm place 
and with their cut ends in water. 

3. The axis. — Cut a bud in two lengthwise, and 

notice that the axis of the bud is the continua- 
tion of the stem. What structures do you find 
borne upon the axis ? To what extent are these 
structures developed? 
Make a diagram showing the structures borne by the 
axis. 

In what respects does a bud resemble a seed ? 

A stem ? In what ways does it differ from a seed ? 

Examine buds from different kinds of trees, 

and compare with the horse-chestnut bud. 

Compare an onion with a bud. 

Make drawings of the buds found on all of the stems 

examined. 



362 THE BIOLOGY OF THE PLANT 

Microscopic Characters. 

Make longitudinal sections passing through the 
middle of the bud, and under the low power note 
the arrangement of the scales, joung leaves, and 
flowers, if any. Under the high power study the 
more minute structure of the various parts, the 
course of the fibro- vascular bundles, the structure 
and development of the glandular hairs, the ar- 
rangement of cells at the growing point, etc. 

Make transverse sections and compare with 
the others. 
Draw sections of each bud examined. 

E. — Leaves 

Material. — Fresh material is best, but pressed leaves 
or those preserved in alcohol may be used. To show 
the changes which take place during the season, particu- 
larly those which affect cell contents, provide leaves 
gathered in the spring, in midsummer, and in the au- 
tumn. 

For the study of the gross anatomy use leafy branches 
from the morning-glory, violet or pansy, maple, dande. 
lion, clover, horse-chestnut, elm, bean, locust, grass, pine, 
honeysuckle, oleander, strawberry, Geranium, Nastur- 
tium, etc. In the physiological experiments entire plants 
of the Geranium, Begonia, Fuchsia, corn, primrose, and 
sensitive plant will be used. 

The apparatus and instruments needed are scalpel, 
hand-lens, compound microscope, thread, metric scale, 
razor, Schulze's solution, phloroglucin, acetic acid car- 
mine, strong alcohol, dilute iodine, vaseline, balance, 
bell-jar, half a yard of rubber cloth, small thistle tube, 
tin-foil, watch-glasses, four large tumblers, and two 



THE FLOWERING PLANT — LEAVES 363 

pieces of cardboard, each sufficiently large to cover the 
tumblers. 

Method of Examination. — Handle the fresh leaves as 
little as possible, and keep in a closed box all those 
which are not in actual use, for in some cases even a 
short exposure to the air causes the leaf to wither. 
Soak alcoholic material previous to examination for two 
or three hours in a mixture of equal parts of fifty per 
cent, alcohol and glycerine, and examine in the mixture. 

MORPHOLOGY 

Gross Anatomy. 

Using the leafy branches of the plants named, 
study the following : 

a. Arrangement or phyllotaxy. — Are the leaves ar- 
ranged alternately or opposite to each other on 
the stem ? If the former, tie a fine thread around 
the base of the stalk of the lowest leaf. Revolve 
the stem between the fingers, and tie the thread 
in like manner around the stalk of the second 
leaf ; again, around the third leaf, and so on, until 
the thread arrives at a leaf which stands directly 
above the first. Counting from the latter, what 
is the number of the leaf which stands over the 
first? How many revolutions of the stem has 
the thread made ? Make a list of plants in which 
the leaves have this spiral or alternate arrange- 
ment. Make another list of plants whose leaves 
are opposite. Do you find any specimens in 
which three, four, or five leaves form a circle, 
called a whorl or verticil, around the stem? 
Make diagrams showing the leaf arrangement of 
each specimen examined. 



364 THE BIOLOGY OF THE PLANT 

h. Structure. — Notice that the leaf consists of a stalk, 
the petiole, which, in the case of simple leaves, 
bears a single flat expansion, the blade, or, as 
in compound leaves, several such expansions, 
the leaflets. Arrange all of your specimens in 
two groups, putting the simple leaves in one 
group and the compound in the other. Write a 
list of the specimens included in each group. 
Sometimes the petiole bears on its lower end a 
pair of expansions, the stipules. Make a list of 
all your specimens which bear stipules, i. e., are 
stipulate ; another list of the exstipulate 
leaves. In some cases no petiole is to be found. 
Make a list of such sessile leaves. 

Study all the leaves with regard to the follow- 
ing points : 

1. The petiole. — What is its shape? Length? 

Diameter? Is it marked by a furrow or 
channel ? If so, on which side of the petiole is 
it ? What is the nature of the surface of the 
petiole ? What is the shape of its base ? 

2. The blade or lamina. — Examine first the sim- 

ple leaves. Is the blade in all cases distinctly 
separated from the petiole ? What is its color ? 
What is the general shape of the blade ? Does 
it consist of a single, entire piece, or is it vari- 
ously lobed ? What is the shape of the apex ? 
Of the base? Of the margin? What is the 
texture of the leaf ? Does the lower side differ 
from the upper ? 

Study the arrangement of the veins (vena- 
tion) in the blade. At what point do the prin- 
cipal veins begin ? Do you in all cases find a 
single large vein or midrib running from the 









THE FLO WEEING PLANT — LEAVES 365 

base to the apex of the blade ? Have you any 
specimens in which a number of large veins 
of about the same size run lengthwise of the 
blade, thus illustrating longitudinal or par- 
allel venation ? Make a list. In which leaves 
do the most of the large veins unite to form a 
network, thus showing reticulated or netted 
venation? Make a list. In a third list put 
all of the leaves in which the veins radiate 
from the base to the margin of the blade, ex- 
amples of radiate, digitate, or palmate ve- 
nation. Can you trace any relation between 
the venation and the outline of the blade ? 
Are the veins composed of more or less firm 
tissue than the rest of the blade % Do the veins 
form a support for the other tissues ? Hold a leaf 
between yourself and the light, and look to see 
if the veins near the margin are so arranged as 
to offer resistance to tearing the soft tissues of 
the blade. Do you find any large areas into 
which the veins do not penetrate 1 
3. The stipules. — What is their shape ? What va- 
riations in shape ? How are they attached to 
the petiole? In what respects do stipules re- 
semble the leaf- blade % 
Draw each of the simple leaves, showing its exact 
shape and venation. 

Examine the compound leaves in like man- 
ner and draw each. 

Can you arrange any of the specimens in a 
series to show how compound might be derived 
from simple leaves ? 



366 THE BIOLOGY OF THE PLANT 

Microscopic Characters. 

Make cross and longitudinal sections of the 
various petioles, and compare them with one an- 
other and with sections of the stem. At least 
three cross - sections of each petiole should be 
made — the first at the base, the second near the 
middle, and the third near the apex. Note the 
tissues present, their arrangement, and the distri- 
bution of the fibro-vascular bundles. Study sur- 
face sections showing the epidermis. 

Examine both surfaces of each leaf with the 
low power, noting the areas into which the small 
veins divide the soft tissues and the distribution 
of stomata. Make sections and study the struct- 
ure of each leaf, noticing especially the arrange- 
ment and structure of the epidermal cells, of the 
green tissue or mesophyll — some of whose cells 
form the palisade parenchyma, next the epi- 
dermis — the contents of the various cells, and the 
arrangement and structure of the fibro-vascular 
bundles. 

Make the drawings necessary to show the facts 
observed. 

How many and which leaves show decided 
structural differences between the upper and 
lower surfaces? What are these differences in 
each case? What reasons can you give for the 
arrangement and contents of the palisade cells ? 
Compare the structure of leaves w T ith that of the 
fern frond examined, and with the thallus of 
Marchantia. 



THE FLO WEEING PLANT LEAVES 367 



PHYSIOLOGY 

A. — Transpiration. 

a. Provide two large tumblers, a piece of cardboard 
large enough to cover the mouth of each, and a 
large leaf of primrose or Geranium or other suit- 
able plant. Fill the first tumbler nearly full of 
water. In the card punch a hole, into which the 
petiole of the leaf will fit snugly, but will not be 
compressed. Put the card over the first tumbler, 
insert the petiole until its lower end projects into 
the water, then set the second tumbler inverted 
over the leaf and resting on the card. As a con- 
trol experiment arrange without the leaf two 
other tumblers, supported by a piece of cardboard 
in which no hole has been made. Let the exper- 
iment stand for a few hours, then examine the 
upper tumbler in each case. Has any moisture 
condensed on the inside ? Whence does the moist- 
ure come % 

h. From a Geranium, Begonia, Fuchsia, sunflower, or 
maple, cut a large, well-developed leaf, seal up the 
cut end of the petiole with vaseline, lay the leaf 
in one pan of a delicate balance, weigh the leaf 
accurately, and make a note of the weight. Let 
the leaf remain on the balance. How long before 
the pans change position ? At the end of half an 
hour balance the leaf again. How much weight 
has it lost ? "Weigh the leaf again at the expira- 
tion of twenty -four hours. What is the loss? 
Has the leaf shrunken in size ? What percentage 
of its weight has been lost by the evaporation of 
water from its tissues ? Compare the weight of 



368 THE BIOLOGY OF THE PLANT 

water lost by a leaf freely exposed to the air with 
that lost by another leaf kept under a bell-jar or 
in a closed box. 

c. Take a small plant like a primrose or begonia, 
growing in a flower-pot, closely wrap the entire 
flower-pot and the lower portion of the stem of 
the plant in rubber cloth such as dentists use, thus 
preventing any evaporation of water from the sur- 
face of the soil or through the flower-pot. Insert 
through the rubber into the soil a small thistle 
tube, so that water may be supplied to the roots 
as needed. "Weigh the plant as thus arranged 
and make a note of the weight. At the end of a 
day weigh again and compare with the previous 
weight. How much water is transpired by the 
leaves in twenty-four hours in an ordinary living- 
room % Does a collection of plants in a room help 
to keep the air moist? If the weather be favora- 
ble, set the plant out of doors overnight and find 
how much moisture is transpired. Compare this 
with the amount lost during the same number of 
hours of exposure to the sun. Judging from your 
experiments, what relations exist between the 
transpiration of water by plants and the humid- 
ity of the atmosphere ? 

B. — Assimilation. 

With a piece of tin-foil wrap both surfaces of 
the lower end of a leaf of a Geranium, Begonia, 
or corn plant, so as to exclude the light from 
that part of the leaf. Let the plant stand for 
several days exposed to the sunlight. At the end 
of that time cut off the leaf, place it for a few 



THE FLOWERING PLANT — FLO WEES 369 

minutes in boiling water, then for a day, or until 
bleached, in strong alcohol. Then place the leaf 
in a weak alcoholic solution of iodine. Does the 
covered assume a color different from that of the 
uncovered portion ? Explain the conditions of 
the experiment and the result. 



0. — Movements. 






If a Clematis be accessible, study the manner 
in which the vine climbs. 

Note the position assumed at night by the leaf- 
lets of the clover, bean, and locust. 

At the greenhouse procure vigorous specimens 
of the sensitive plant, and by various methods, 
which are left to the student to devise, test the 
irritability of the leaves and study their change 
of position. 

If specimens of the sundew and of Yenus's fly- 
trap can be had, study the movements of the tri- 
chomes and of the leaf-blade. If time permits, 
repeat some of the experiments detailed in Dar- 
win's " Insectivorous Plants." 



F. — Flowers 

Material. — In the case of large plants, as the cherry 
and apple, bring to the laboratory some of the branches 
with the flowers attached rather than the individual 
flowers. 

As other specimens, bring violets or pansies, butter- 
cups, morning-glories, dandelions, peas, or beans. 

For the study of the developing flower either fresh or 
alcoholic material may be used. Forceps, scalpel, hand- 
24 



370 THE BIOLOGY OF THE PLANT 

lens, microscope, razor, watch-glasses, dilute iodine, and 
acetic acid carmine will be needed in the examination. 

Method of Examination. — Study first the fiower in its 
natural surroundings, especially the plants among which 
it grows, the time of year during which it is in blossom, 
and the kinds of insects found to visit it, for much of the 
significance of the structure, color, etc., of a flower is to 
be learned only from a study of its surroundings and of 
other parts of the plant. 

MORPHOLOGY 

Naked-eye Characters. 

Take a cherry branch bearing several blossoms 
in various stages of expansion and study the fol- 
lowing : 

a. Arrangement or anthotaxy. — On what part 6f the 

stem are the blossoms borne ? What position do 
they have with regard to one another ? Is this con- 
stant ? How many do you find in a cluster ? Is 
the number invariable ? What is their position 
with regard to the leaves? Make a diagram indi- 
cating the position of the clusters on the stem ; 
another, showing the position of the flowers in a 
cluster. 

b. Shape. — What is the shape of a mature but un- 

opened bud? Draw. Of an expanded flower? 
Draw. What reasons can you give for these facts ? 

c. Size. — What is the diameter of a mature bud ? Of 

an expanded flower ? Does the flower grow as it 
opens ? 

d. Color. — What is the color of a perfect blossom ? 






THE FLOWERING PLANT FLOWERS 371 

Are there any variations from this color ? Do all 
the parts of the flower have the same color ? Is 
it always the same part that is colored ? To what 
is the color due ? Crush one of the colored parts 
by pinching it between the thumb and finger. 
Does the color change ? Why ? Does the color 
change as the flower gets older ? Why ? Of what 
use is the color ? 

e. Odor. — Has the flower a well-defined odor? Is it 

characteristic ? Is it a strong odor ? Agreeable 
or disagreeable ? Is it confined to any particular 
part of the flower ? Does it vary in intensity at 
different times of the day ? Why ? Of what use 
is it? 

f. Structure. — Proceeding from below upwards make 

out the following parts : 

1. The pedicel or flower-stalk. — What is its shape? 

Color? Length? Diameter? Do any of these 
vary in different flowers? Of what use are 
these various characters ? Draw a pedicel de- 
tached from other parts. 

2. The flower proper. — Note that it consists of 

certain organs arranged in groups. How are 
these organs distinguished from one another ? 
What is the shape of the groups? In what 
manner are they attached to the pedicel ? Note 
the expanded end, or receptacle, of the pedi- 
cel. Proceeding from without inward, make 
out the following parts of the flower proper : 
(a) The calyx or green part. — On what part of 
the flower is it found ? Is it evenly green in 
color ? What is its shape ? Of what is it made ? 
Does it consist of distinct parts or sepals? 



372 THE BIOLOGY OF THE PLANT 

Note the calyx-tube and the limb or border. 
How do they differ ? What is the diameter of 
the tube ? Depth? The length of the lobes 
of the limb ? Width ? Is their size constant ? 
How many lobes are there ? Is the number con- 
stant ? What position have these lobes in a bud? 
Why ? Is it different in the expanded flower ? 
Why ? Note the character of the surface and 
margins of the parts of the calyx. Look for 
nectar in the calyx. What is its color ? Con- 
sistence ? Taste ? Why is it in this part of the 
flower ? Do you find any elsewhere ? What is 
its use ? Why is the base of the calyx cup- 
shaped ? Of what use is the calyx ? What be- 
comes of the calyx as the flower becomes older 
and the fruit begins to form ? Do you find in 
the ripe fruit any trace of the calyx ? Are the 
parts of the calyx at all leaf -like in character ? 
Draw a calyx as seen from above and as seen 
in longitudinal section. 
(b) The corolla or colored part. — What position 
does it occupy in the flower ? What is its gen- 
eral shape ? Of what use is the shape ? Of 
how many parts or petals does the corolla con- 
sist ? Does the number vary in different flow- 
ers? How does the number of petals corre- 
spond with the number of sepals ? To what 
other parts are they attached ? In what man- 
ner ? What is their shape ? Size ? Color ? Are 
all of the same shape? Of the same color? 
What is the use of the color ? What is the char- 
acter of the surface and margins of the petals ? 
Of the apex, and base or claw ? What is the 
structure of a petal? What position have the 



THE FLO WEEING PLANT FLOWERS 373 

petals with regard to the calyx lobes ? In what 
respects do the petals resemble leaves ? What 
position have the petals in unopened buds? 
What is the use of the corolla? 

Draw the entire corolla and several of the 
petals. 
(c) The andrcecium, consisting of the stamens. 
— What is its position in the flower ? Does it 
bear any resemblance to the calyx and corolla ? 
Does every blossom contain an andrcecium? 
How many stamens in the andrcecium ? How 
are they arranged with regard to the calyx and 
corolla and with regard to one another ? Are 
they all of the same shape ? Size ? Color ? 
Make a diagram of the andrcecium, showing the 
arrangement of its parts. 

Examine a single stamen and make out the 
following parts : 

(1) The filament or stalk. — What is its shape ? 
Length ? Do you find variations in length ? 
Can you give reasons for the same ? What is 
its diameter ? Color ? Does it bear any out- 
growths, such as hairs ? If so, where are 
they ? Why here ? 

(2) The anther. — What is its position on the 
filament? Shape? Size? Color? To what 
is the color due? Make out the two parts, 
pollen-sacs, of the anther joined by the con- 
nective, also the lines of dehiscence along* 
which the sacs split open. Can you trace 
any resemblances between the anther of a 
flower and the sporangium of a fern ? Draw 
a stamen. Note the fine powder or pollen 
which comes out of the sacs. Put some of 



374 THE BIOLOGY OF THE PLANT 

the pollen on a slide without a cover-glass 
and examine with the low power. 
(d) The gynaecium, consisting of the pistil. — 

What relation does it bear to the other groups ? 

Is it present in all of the blossoms ? In what 

way does it resemble any of the other parts ? 

Draw the gynaecium. 

The pistil consists of the following parts 

named from below upwards : 

(1) The ovary, at the base of the pistil. — How 
much of the pistil does it form? What is 
its shape? Color? To what is it attached? 
Open it and notice the seed with its con- 
tained ovule. What is its structure ? What 
part of the fruit does the wall of the ovary 
become ? What part the seed ? What changes 
in shape, size, color, and structure take place 
as ripening goes on ? 

(2) The style or stalk of pistil. — What is its 
position? Shape? Size? Color? Compare 
with the filament of a stamen. Is the divid- 
ing line between style and ovary well marked ? 
Why called "style"? What becomes of the 
style as the fruit ripens ? 

(3) The stigma or top of style. — What is its 
shape? Size? Color? Of how many parts 
or lobes does it consist ? Examine the sur- 
face of a mature stigma for pollen grains. 
What holds them in place? How do they 
get from the anther to the stigma? Why 
named " stigma " ? 

Compare with this flower others taken from the 
apple or pear tree, bean or pea, violet or pansy, 
buttercup and the dandelion, noticing especially 






THE FLOWERING PLANT FLOWERS 375 

the various structural modifications which the 
parts undergo in each flower. Make a diagram 
of a cross - section of each flower, showing the 
number and position of all the parts, also a draw- 
ing twice natural size of one of each of the floral 
organs showing its shape and structure. Examine 
old flowers and young fruits of each plant, and 
trace the changes which take place in the parts 
of the flower. In which flowers do you find 
organs of the same kind grown together, illus- 
trating coalescence? In which, organs of dif- 
ferent kinds, adnation? In which do you find 
the parts of any group of organs unlike in shape, 
examples of irregularity? Endeavor to ac- 
count for the various shapes,, colors, arrange- 
ment of parts, etc., found. In what way does 
a flower resemble a bud? A leafy branch? 
Which of the flowers illustrate symmetry, i. e., 
have the same number of parts in each group of 
organs, or have a certain number in some groups 
but a multiple of that number in the remaining 
groups ? 

Microscopic Structure. 

Section the pedicel of the flower and compare 
its tissues, vascular bundles, etc., with those of 
the stem and of the petiole. Examine the sepals 
and petals and compare with one another and 
with leaves. Draw all of the sections. Study 
the structure of the filament and anther and ex- 
amine the pollen. What is the shape of the 
pollen grains? Color? Do they bear any mark- 
ings or projections on the surface? Do you find 
variations in any of these particulars ? What is 



376 THE BIOLOGY OF THE PLANT 

the structure of a pollen grain ? Does a pollen 
grain in any way resemble a fern spore ? Draw 
several pollen grains. Examine sections through 
a young and through a mature anther. Does it 
resemble a sporangium? Is it at all leaf -like in 
structure ? Study cross and longitudinal sections 
of the various parts of the pistil. Note particu- 
larly the structure of the ovary, the number and 
position of the ovules, the ridge or placenta, to 
which each of the latter is attached by the stalk 
or funiculus^ In favorable longitudinal sections 
through an ovule try to find the central portion, 
the nucellus, surrounded by two coats, the inner 
or primine and the outer or secundine. Be- 
tween the edges of the former look for an open- 
ing, the micropyle, and near the centre of the 
nucellus a large cell, the embryo-sac. In which 
direction does the micropyle point ? Draw. Which 
of these parts are apparent in the mature seed? Is 
the pistil in any respect leaf -like ? 

Study very young flower buds, and endeavor to 
trace the origin and development of the various 
floral organs. 

PHYSIOLOGY 

a. Fertilization. 

With a lens examine the pistils of various flow- 
ers, as lily, pumpkin, Gloxinia^ etc., for pollen 
grains which have become attached to the stig- 
ma. Having found such a pistil, remove it and 
make longitudinal sections. Some of these will 
probably show growing down into the tissues of 
the style the tube emitted by the pollen grains. 
Trace the tubes as far as possible and make the 



THE FLOWERING PLANT FLOWERS 377 

necessary sketches. Make longitudinal sections 
of the ovary to find pollen tubes penetrating the 
ovule. 

Examine various flowers to answer the follow- 
ing questions : Is the pollen set free at the time 
the stigma becomes mature, which state is usually 
shown by a viscid secretion on its surface ? Is the 
pollen in such a position and of such structure that 
it may fall or be blown upon the stigma ? Do the 
stamens grow in such a position or are they of 
such shape that, if an insect were to alight upon 
the flower or to enter it, some of the pollen would 
be dusted upon or would adhere to his body ? Is 
the pistil in such a position that a visiting insect 
would rub against it ? If the flower secretes nec- 
tar, is it in such a place that, in order to get it, 
the insect must brush against stamens or pistil or 
both ? Is the nectar freely exposed, or is it at the 
bottom of a tube, out of the reach of all insects 
except such as have a long proboscis, or is the 
entrance to the place where the nectar is stored 
guarded by hairs, bristles, etc. ? 



APPENDIX 



A. — List of Reagents, etc. 

1. Acetic Acid. 

Use. — Clears opaque tissues and thick sections ; swells 
cellulose walls and starch grains ; dissolves crystals of 
calcium carboDate with effervescence. Dilute solutions 
bring out nuclei very clearly. 

Preparation. — To prepare the dilute, or one per cent, aque- 
ous solution, dissolve one gram of glacial acetic acid in 
ninety-nine cubic centimetres of distilled water. 

2. Acetic Acid Carmine (Schneider's). 

Use. — Stains fresh tissues rapidly ; makes the nucleus show 
plainly. 
' Preparation. — From glacial acetic acid prepare a solution 
of forty-five per cent, strength. Heat this solution to 
the boiling-point, and while at this temperature add 
finely pulverized carmine until no more will dissolve. 
Filter the mixture and use it concentrated, or, better, 
diluted to one per cent. The latter strength stains more 
slowly than the former. 

3. Alcohol. 

Use. — Of all reagents alcohol is used most frequently, and 
in the largest amount. It is not only a hardening agent 
and a preservative for permanent preparations, but in 
the diluted form is used in the examination of preserved 
specimens ; consequently, a large supply should be kept 



380 APPENDIX 

on hand. To purchase alcohol at the regular market 
price, which is about two and a half dollars per gallon, 
entails upon the laboratory a serious expense, which, 
with little trouble, may be avoided. By act of Con- 
gress every incorporated educational institution is per- 
mitted to purchase alcohol free of the internal revenue 
tax when the alcohol is to be used for scientific pur- 
poses only. Before the alcohol may be withdrawn from 
the bonded warehouse in which it is stored, certain pre- 
liminaries must be performed. These are as follows: 
From the collector of internal revenue for your district 
learn where the nearest distillery is located ; write to the 
distiller, specifying the amount of alcohol desired ; in re- 
turn you will receive a bond, an application for the with- 
drawal of alcohol from bond, and a gauger's receipt 
specifying the number, etc., of the package of alcohol 
which has been set aside for you ; you will then fill out 
the application with the name of the institution, curator, 
etc., and forward it to the Secretary of the Treasury, 
along with the gauger's receipt and the bond, the latter 
having been signed previously before a notary -public, 
and in the presence of two witnesses, by the principal 
officer or curator of the institution and two sureties. 
In due time the distiller will receive from Washington a 
permit for the withdrawal from bond of the package of 
alcohol which you wish to purchase. This will then be 
forwarded you. By observing such procedure alcohol 
may be obtained for about seventy-five cents per gallon, 
or less than one-third the market price. 

Absolute alcohol comes in one-pound bottles, and is 
used as a killing and hardening agent. Objects killed in 
this may be preserved in seventy per cent, alcohol. 
Preparation. — As procured in the market or from the dis- 
tillery, alcohol varies from ninety to ninety-five per cent, 
in strength. From this the various grades may be pre- 
pared approximately by mixing ninety -five per cent, 
alcohol and water in the proportions given in the fol- 
lowing: table : 



LIST OF KEAGENTS, ETC. 



381 



3r cent. 


Alcohol 


Water 


Per cent. 


Alcohol Water 


84 


6 


1 


48 


1 1 


82 


5 


1 


45 


1 1.25 


78 


4 


1 


42 


1 1.5 


75 


3 


1 


35 


1 2 


67 


2 


1 


SO 


1 3 


62 


1.5 


1 


22 


1 4 


60 


1.25 


1 


18 


1 5 


55 


1.1 


1 


— 


— — 



4. Alcoholic Carminic Acid. 

Use. — Stains rapidly the protoplasm and nuclei of fresh or 

alcoholic specimens. 
Preparation. — The crystals of carminic acid come in small 

vials. A sufficient number of the crystals may be added 

to alcohol of any strength until a solution of the desired 

depth of color has been produced. 

5. Barium Hydrate. 

Use. — The solutions of barium hydrate are used to detect 
the presence of carbon dioxide, which unites with the 
barium hydrate and forms a white precipitate of barium 
carbonate. 

Preparation. — Add barium oxide to distilled water until a 
saturated solution is formed. 

6. Bristles. 

These are used to insert into and follow the course of 
blood-vessels, ducts, etc. Their ends should be guarded 
by a small knob of sealing-wax. It is convenient to 
have bristles of various lengths, colors, and degrees of 
stiffness. They may be obtained from manufacturers of 
paint-brushes. 

7. Chloral Hydrate. 

Use. — Anaesthetic and antiseptic ; clears pollen-grains, etc. 

Preparation. — Add two grams of the crystals to ninety- 
eight cubic centimetres of distilled water. This solution 
may be added drop by drop to the water containing small 
animals which it is desired to anaesthetize. 



382 APPENDIX 

8. Chlor-iodide of Zinc (Schulze's Solution). 

Use. — A delicate test for cellulose ; turns cellulose cell- 
walls and starch grains blue, protoplasm brown, and 
corky and lignified cell-walls brown. 
Preparation. — To strong hydrochloric acid add some pure 
zinc until no more will dissolve. Set the solution in a 
warm place, add more zinc, and evaporate the fluid un- 
til it has a syrupy consistency. To the solution add 
crystals of potassium iodide until no more will dissolve, 
then saturate the mixture with metallic iodine. This 
gives a dark -brown, concentrated solution, which may 
be diluted until it has the color of sherry-wine by add- 
ing the requisite amount of a solution of one part of 
potassium iodide dissolved in twenty parts of water. 
Keep the solutions in a dark place. 

9. Chromic Acid. 

Use. — A one-half per cent, solution may be used for hard- 
ening tissues ; strong aqueous solutions dissolve lignified 
and cellulose cell-walls. 

Preparation. — Chromic acid comes in the form of red crys- 
tals. Make a four per cent, solution by dissolving four 
grams of the crystals in ninety-six cubic centimetres of 
distilled water. Dilute this solution as required. Keep 
the solutions of chromic acid in the dark. 

10. Copper Sulphate. 

Use. — Used with sodium hydrate as a test for glucose and 

for albuminous (proteid) substances. 
Preparation. — Dissolve one gram of the crystals of copper 

sulphate in ninety -nine cubic centimetres of distilled water. 

11. Corrosive Sublimate. 

Use. — Is a hardening agent, and kills small animals almost 
instantaneously. Do not handle with steel instruments 
specimens killed in corrosive sublimate. 

Preparation. — Saturate distilled water with mercuric chlo- 



LIST OF REAGENTS, ETC. 383 

ride. One litre of water will dissolve about seventy grams 
of mercuric chloride. 

12. Delafield's Hematoxylin. 

Use. — One of the best of stains for alcoholic material. 
Must not be used until specimen has been freed from 
any acids that may have been used in the process of 
preservation. In staining add a few drops of the solu-' 
tion to distilled water until the desired depth of color is 
obtained, then immerse the specimen. Dilute solutions 
stain much more satisfactorily than concentrated, though 
longer time is required. 

Preparation. — Dissolve four grams of hsematoxylyn crys- 
tals in twenty-five cubic centimetres of ninety per cent, 
alcohol. Saturate four hundred cubic centimetres of dis- 
tilled water with ammonia alum ; to this add the first solu- 
tion. Let the mixture stand exposed to the light and air 
in an open bottle for three or four days ; then filter, and 
to it add one hundred cubic centimetres of glycerine and 
one hundred cubic centimetres of methyl alcohol. Let 
the mixture stand for a time, then filter again, and keep 
in a stoppered bottle. The stain works best if allowed 
to ripen for two or three months before using. 

13. Dissecting-Dishes. 

These may be of tin or earthenware. If the latter, ordi- 
nary vegetable dishes will serve. A convenient tin dish 
is a foot long, six inches wide on the bottom, seven or 
eight inches wide on top, and two and one-half to three 
inches deep. The bottom of the dishes should be cov- 
ered by a layer one-quarter to one-half inch thick of 
beeswax or paraffin which has been mixed with lamp- 
black. A dark background is thus formed against which 
the delicate tissues of the various specimens show well, 
and the parts may be displayed by pinning them out on 
the wax. It will be found that the pins will hold better 
in beeswax than in paraffin. Before pouring the melted 
wax into the dishes, put into the bottom of each a num- 



384 APPENDIX 

ber of large shot to weight the wax, otherwise, as it 
separates from the sides of the dish in cooling, it will 
float when water is poured into the dish. If tin dishes 
be used, smear some of the melted wax over the inside 
of each to prevent rusting. The dishes should be washed 
and thoroughly dried after being used. 

14. D is sec ting-Needles. 

These are invaluable in the examination of small organ- 
isms, pieces of tissue, etc. They may easily be made by 
thrusting the eye end of sewing-needles into pen-holders 
made of soft wood. It is well to have several pairs 
made with needles of different sizes. 

15. D is sec ting- Trays. 

Convenient trays may be made of deal boards measur- 
ing eighteen by twelve inches. They may have a narrow 
moulding or a deep groove at the edge to catch the 
fluids and prevent them from soiling the tables. The 
trays should be thoroughly oiled before being used, as 
the oil prevents the wood from absorbing fluids and fa- 
cilitates cleaning. If desired, the trays may be stained 
black with a solution of logwood before being oiled. They 
should be thoroughly cleansed each time after using. 

16. Eosin. 

Use. — Stain for alcoholic or fresh tissues. 

Preparation. — Prepare the alcoholic solution by dissolving 
one gram of eosin in ninety-nine cubic centimetres of 
ninety-five per cent, alcohol. When using, add this solu- 
tion to alcohol in the proportion of one drop of the 
former to twenty drops of the latter. The aqueous solu- 
tion is prepared by dissolving in distilled water sufficient 
eosin to produce the depth of color desired. 

17. Glycerine. 

Use. — Clears tissues; serves as a temporary mounting 
medium. 



LIST OF REAGENTS, ETC. 385 

Preparation. — Either concentrated glycerine or the dilute 
solution may be used for mounting. The latter is made 
by mixing equal parts of glycerine and distilled water. 

18. Hydrochloric or Muriatic Acid. 

Use. — Dissolves crystals of calcium carbonate and of calcium 
oxalate, the former with the latter without effervescence ; 
decalcifies ; macerates ; turns lignified cell-walls yellow. 

Preparation. — The concentrated acid, which is perfectly 
colorless, may be diluted with distilled water to the va- 
rious strengths needed. Keep in glass-stoppered bottles. 

19. Injection Masses. 

Starch. — The starch injection mass serves well for coarse 
anatomical work, and is easily managed. The mass it- 
self consists of one volume of dry starch, one volume of 
a two and a half per cent, aqueous solution of chloral 
hydrate, one-fourth volume of ninety-five per cent, alco- 
hol, and one -fourth volume of the color. The last is 
prepared by mixing together equal volumes of the dry 
color — e. g., vermilion or soluble Prussian blue, glyce- 
rine, and ninety-five per cent, alcohol. These ingredients 
should be thoroughly ground together in a mortar, and 
strained through fine muslin to remove the lumps which 
might clog the cannulse of the syringe. This color mixt- 
ure may be kept permanently in a closed bottle, and 
added to the starch mass as desired. 

Gum-arabic. — Make a thick paste by dissolving gum-ara- 
bic in water to which has been added sufficient soluble 
Prussian blue to produce the desired depth of color; 
strain the paste through fine muslin ; place the injected 
specimen in alcohol to harden the paste. 

20. Iodine. 

Use. — Colors starch blue, proteid substances (protoplasm, 
etc.) brown, cellular cell-walls light-yellow, cuticularized 
and lignified cell-walls yellow. 

Preparation. — Dissolve to saturation crystals of potassium 

25 



386 APPENDIX 

iodide in distilled water ; then saturate the solution with 
metallic iodine. Dilute this with one to three times its 
bulk of distilled water as desired. Keep all solutions of 
iodine in the dark. 

21. Magenta. 

Use. — Stains fresh tissues. 

Preparation. — Dissolve one gram of crystallized magenta 
(roseine) in ninety -nine cubic centimetres of ninety -five 
per cent, alcohol. Dilute this to any strength needed by 
adding distilled water. 

22. Mayer's Pepsin Solution. 

Use. — Culture-medium for yeast, etc. 

Preparation. — The following formula is taken from Huxley 
and Martin's " Practical Biology" : 

Fifteen per cent, solution of sugar candy 20 cubic centimetres 

Dihydropotassic phosphate .... 0.1 gram 

Calcic phosphate 0.1 " 

Magnesic sulphate 0.1 " 

Pepsin 0.23 " 

23. Millorfs Reagent. 

Use. — Turns albuminous (proteid) substances red. 

Preparation. — Dissolve metallic mercury in its own weight 
of strong nitric acid. This is best done by pouring the 
acid upon the mercury in a beaker. As suffocating 
fumes and considerable heat are generated, it is best to 
place the beaker on a cloth under a ventilating hood, or 
on a ledge outside the window. When the mercury is 
entirely dissolved add to the solution twice its volume of 
distilled water. Let the mixture stand for a few hours, 
then decant it into a glass-stoppered bottle. 

24. Moist Chamber. 

A very simple form of moist chamber in which to ex- 
amine cultures of spores, pollen-grains, etc., is made in 
the following manner : From a piece of smooth paste- 



LIST OF REAGENTS, ETC. 387 

board of medium thickness cut a square which does not 
exceed a glass slide in width ; in the centre of the square 
4 cut a circle whose diameter is somewhat less than that 

of a cover-glass ; immerse the frame thus made in strong 
alcohol for a few hours in order to kill any organisms 
that may be attached to the pasteboard, otherwise they 
may later become active and vitiate the culture ; when 
ready to start the culture remove the frame from the al- 
cohol and soak it in distilled water until thoroughly sat- 
urated, then lay the frame on the glass slide ; in the 
centre of the cover-slip put a drop of the culture-fluid, 
which has previously been sterilized by boiling ; sow in 
the drop a few of the spores which are to be cultivated ; 
then, with the drop hanging from the under side, place 
the cover -glass on the pasteboard frame, and keep the 
preparation under a bell -jar with a dish of water to 
keep the atmosphere moist and to prevent the paste- 
board from drying; examine the pasteboard frequently, 
and if it shows signs of drying moisten its edges 
with distilled water. It is convenient to keep in strong 
alcohol a permanent supply of these frames. Moist 
chambers may also be made by using glass rings, 
which are furnished by dealers in microscopical sup- 
plies. 

25. Mutter's Fluid. 

Use. — Hardening reagent. Specimens may be left in it 

from two to several weeks. 
Preparation. — In one litre of water dissolve twenty -five 

grams of bichromate of potash and ten grams of sodium 

sulphate. 

26. Nitric Acid. 

Use. — Hardens nerve, macerates muscle, and decalcifies 
osseous tissues ; colors proteids and cuticularized cell- 
walls yellow ; swells cellulose and lignified cell- walls. 

Preparation. — Make dilute solutions from the colorless con- 
centrated acid. Keep in glass-stoppered bottles. 



388 



APPENDIX 



27. Osmic Acid. 

Use. — Kills living protoplasm — e. g., Protozoa, etc., in- 
stantaneously ; fixes nuclei ; and stains fats and oil 
black. 

Preparation. — Crystals of osmic acid come in small tubes, 
each containing one gram. One of these tubes may be 
broken in a bottle containing ninety -nine cubic centi- 
metres of distilled water. This gives a one per cent, solu- 
tion which may be diluted. The bottle should have a 
ground - glass stopper and be kept in a dark place, or 
wrapped with thick, opaque paper. 

28. Pasteur's Solutions. 

Use. — Culture-media for yeast, mould, spores of fungi, etc. 

Preparation. — The following formula for making the solu- 
tion " with sugar " is given in Huxley and Martin's 
" Practical Biology " : 



Potassium phosphate . . . 
Calcium phosphate .... 
Magnesium sulphate .... 
Ammonium tartrate .... 

[Cane-sugar] 

Water 


. . . . 20 parts 
. . . . 2 " 
. . . . 2 " 

. ... 100 " 
. . . . 1,500 " 
. . . .8,376 " 




10.000 parts 



The solution " without sugar " is the same as the above 
with the sugar omitted. 



29. PerenyVs Fluid. 

Use. — Kills small animals, eggs, etc., instantaneously. Ob- 
jects may be left in it from two to five hours, then trans- 
ferred to seventy per cent, alcohol for a day, then to 
ninety per cent, alcohol. 
Preparation. — Mix together four parts of a ten per cent, 
solution of nitric acid, three parts of a one-half per cent, 
solution of chromic acid, and three parts of ninety per 
cent, alcohol. 



LIST OF REAGENTS, ETC. 389 

30. Picric Acid. 

Use. — Hardens tissues in two or three hours to a day, ac- 
cording to the size of the piece, and decalcifies bony struct- 
ures. Remove the excess of picric acid by washing in 
alcoho], and stain picric acid preparations in alcoholic 
stains. Transfer specimens fixed in picric acid to seven- 
ty-five per cent., and then to ninety-five per cent, alcohol. 

Preparation. — A saturated aqueous solution is made by 
adding crystals of the acid to distilled water until no 
more will dissolve. 

31. Picro-sulphuric Acid (Kleinenherg 's). 

Use. — Hardens and decalcifies. To harden objects place 
them in the fluid for three to five hours, transfer to 
seventy per cent, alcohol for five to six hours, then place 
in ninety per cent, alcohol, and chaDge the latter as of- 
ten as it becomes discolored. 

Preparation. — To one hundred volumes of a saturated so- 
lution of picric acid in distilled water add two volumes 
of concentrated sulphuric acid. Filter this mixture 
and dilute it with three times its volume of distilled 
water. 

32. Pith. 

Bunches of pith may be obtained from dealers in watch- 
makers' supplies. 

33. Potash. 

Use. — Clears vegetable tissues by causing the cell -walls, 
starch grains, etc., to swell, and the proteid crystalloids 
and aleurone to dissolve. 

Preparation. — Potassium hydroxide comes in the form of 
sticks. These usually have an opaque white coating of 
potassium carbonate, which should be dissolved off, and 
only the central, transparent part of the stick used. 
Make a concentrated solution by dissolving twenty-five 
grams of potassium hydroxide in seventy-five cubic centi- 
metres of distilled water. Make the five per cent, (dilute) 



390 APPENDIX 

solution by dissolving five grams of potassium hydrox- 
ide in ninety -five cubic centimetres of distilled water. 
Keep potasb solutions in bottles with ground-glass stop- 
pers, and smear the latter with vaseline to prevent them 
from becoming fastened in the necks of the bottles. 

34. Reagent Bottles. 

Each table should be supplied with at least one set of 
the common reagents and stains, put up in bottles hold- 
ing two or more ounces, according to the number of stu- 
dents working at the table. If the bottles be circular 
they may be set into a tray made by boring holes of the 
required diameter in a piece of plank an inch or more in 
thickness. The tray will avoid the necessity of a set of 
shelves, which is often in the way, and will keep the 
bottles in a compact space. Each bottle may be closed 
by a bulb stopper which carries a glass pipette and 
serves at the same time for a dropper. These " Stand- 
ard Medicine Droppers" come in boxes containing one 
dozen each, and may be obtained of J. J. Requa, New 
York. Each bottle should also have a label, giving the 
name, composition, and use of its contents. 

35. Sachs's Food Solution for Green Plants. 

Use. — A culture-medium for green plants. 
Preparation. 

Distilled water 1000 cubic centimetres 



Potassium nitrate .... 
Sodium chloride (common salt) 
Calcium sulphate (gypsum) . 
Magnesium sulphate . . . 
Calcium phosphate (pulverized) 



1 gram 
0.5 " 
0.5 " 
0.5 " 
0.5 " 



To the above mixture add five or six drops of a weak 
solution of chloride of iron. 

36. Salt Solutions. 

Use. — The strong solutions are used as plasmolyzing 
agents ; the weak, to form a neutral medium in which 



LIST OF REAGENTS, ETC. 391 



living tissues may be examined without undergoing the 
changes caused by pure water. 
Preparation. — The strong solution (twenty per cent.) may 
be made by dissolving twenty grams of common table salt 
in eighty cubic centimetres of distilled water, and from 
this weaker solutions may be prepared. The " normal " 
(three-quarter per cent.) salt solution is made by adding 
seven and a half grams of salt to one litre of distilled water. 

37. Schulze's Macerating Mixture. 

Use. — Separates the constituent elements of vegetable tis- 
sues by dissolving the middle lamella. Used cold the 
mixture gives better results, but works more slowly than 
when warmed. Do not expose the microscope to the 
fumes given off. 

Preparation. — Dissolve one gram of potassium chlorate in 
fifty cubic centimetres of nitric acid. 

38. Sea-water (artificial). 

The following formula gives an artificial sea -water in 
which starfishes, lobsters, etc., may be kept alive for 
some time : 

Water 3 to 4 litres 

Sodium chloride (salt) 81 grams 

Magnesium sulphate *7 " 

Magnesium chloride 10 " 

Potassium chloride 2 " 

This water should frequently be aerated by pouring from 
a height into the tank. 

39. Silver Nitrate. 

Use. — A stain for fibrous tissues. The tissue to be stained 
is spread upon the slide in a drop of the solution, and 
exposed to the sunlight until a brown color is assumed. 
The preparation is then washed in distilled water. 

Preparation. — Dissolve one -half gram of the crystals of 
silver nitrate in one hundred cubic centimetres of distilled 
water. Keep in the dark in a glass-stoppered bottle. 



392 APPENDIX 

40. Sodium Hydrate. 

Use. — With copper sulphate it forms a test for glucose. 

Preparation. — Dissolve the sticks of sodium hydrate in 
three or four times their weight of distilled water. Keep 
in a bottle with a glass stopper, the latter having been 
smeared with vaseline to prevent sticking. 

41. Sugar. 

Use. — Concentrated solutions plasmolyze living cells ; used 
also as a culture medium for yeast; and to cause the 
germination of pollen-grains. 

Preparation. — To make the twenty per cent, solution dis- 
solve twenty grams of granulated sugar in eighty cubic 
centimetres of distilled water. From this the ten per cent, 
and two per cent, solutions may be made by dilution. 

42. Sulphuric Acid. 

Use. — The concentrated acid dissolves cellulose cell-walls 
and swells starch grains ; turns blue those cellulose cell- 
walls which have previously been saturated with a solu- 
tion of iodine. For the last reaction dilute solutions are 
preferable. 

Preparation. — Dilute the concentrated colorless acid to the 
strength desired. Make the dilute by mixing equal parts 
of the concentrated solution and distilled water ; the sev- 
enty-five per cent, solution by mixing seventy-five parts 
of the acid with twenty -five parts of distilled water. 
Keep in bottles with glass stoppers. 

43. Warm Stage. 

A simple warm stage consists of a T-shaped piece of 
sheet copper six inches long by three inches wide. In 
the middle of the cross-piece is punched a hole whose 
diameter is slightly greater than that of a cover-glass. 
When used the warm stage is placed on the stage of the 
microscope with the tongue projecting forward, and the 
hole over the opening in the stage. On the cross-piece 
is laid the slide, the whole being held securely in place 



LIST OF REAGENTS, ETC. 393 

by the clips 013 toe stage. On or by the side of the 
cover-glass is laid a small piece of paraffin, which melts 
at the temperature at which the object is to be studied. 
Let the tongue of the warm stage project into the flame 
of an alcohol lamp. The tongue of metal will conduct 
the heat back to the preparation on the slide, the tem- 
perature of the latter being indicated by the condition of 
the paraffin, which should be kept at the melting-point, 
but not allowed to become fluid. If the stage become 
too hot, cool it by removing the lamp for a time. 

44. Wicker sheimer' 's Fluid. 

Use. — Small animals — e. g., frogs — may be immersed in this 
fluid for a week or two, then taken out and dried in the 
air. Lungs, blood-vessels, and intestines should be filled 
with the fluid, though this is not necessary in the case of 
animals as small as the frog. The muscles, tendons, and 
ligaments remain soft and flexible, and the natural color 
of the organs is frequently well preserved. 
Preparation. — In three thousand cubic centimetres of boil- 
ing water dissolve one hundred grams of alum, twenty- 
five grams of common salt, twelve grams of potassium 
nitrate, sixty grams of potash, and ten grams of arsenic 
trioxide. Cool and filter the mixture. Then to each ten 
litres of the above mixture add four litres of glycerine 
and one litre of ninety to ninety-five per cent, alcohol. 



B. — Woeks of Befeeence 

Under its proper head, in the following list, will be found 
the titles of books or articles, some of which the student should 
consult in connection with the examination of each organism. 
The list is not intended to be complete, and includes only such 
works as are likely to be found in almost every library. For 
the sake of convenience each title is numbered, and is given in 
full only when first mentioned. 

MICEOSCOPICAL MANIPULATION AND LABOEATOEY METHODS 

I 1. Beale. — " How to Work with the Microscope," London, 
1880. Structure and methods. 

2. Behrens. — " Guide to the Microscope in Botany," Boston, 

1885. Structure and methods. 

3. Bower and Vines. — " A Course of Practical Instruction in 

Botany," New York, 1889. Methods. 

4. Carpenter. — " The Microscope and Its Kevelations," re- 

vised by Dallinger, Philadelphia, 1891. Structure and 
methods. 

5. Fearnley. — " A Course in Elementary Practical Histology," 

New York, 1887. Laboratory and microscopical meth- 
ods. 

6. Frey. — " The Microscope and Microscopical Technology," 

New York, 1872. Structure and methods. 

7. Gage. — " The Microscope and Histology," Part I., Ithaca, 

1891. Structure and methods. 

8. Goodale. — "Physiological Botany," New York, 1885. 

Methods. 

9. Howes. — "Atlas of Practical Elementary Biology," London, 

1885. Methods. 



WORKS OF REFERENCE 395 

10. Huxley and Martin. — "A Course of Elementary Instruction 

in Practical Biology," revised by Howes and Scott, New 
York, 1889. Microscopical and laboratory methods. 

11. Lee. — " Microtomist's Vade Mecum," Philadelphia, 1890. 

Methods. 

12. Marshall and Hurst. — "Practical Zoology," London, 1888. 

Microscopical and laboratory methods. 

13. Poulsen. — "Botanical Micro - Chemistry," Boston, 1886. 

Methods. 

14. Sckafer.— "The Essentials of Histology," Third edition, 

Philadelphia, 1892. Methods. 

15. Strasburger. — "Hand-book of Practical Botany," translated 

by Hillhouse, New York, 1889. Methods. 

16. Whitman. — "Methods in Microscopical Anatomy and Em- 

bryology," Boston, 1885. Methods. 

17. Wilder and Gage. — " Anatomical Technology," New York, 

1886. Laboratory methods. 

GENERAL WORKS ON ZOOLOGY 

18. Claus and Sedgwick. — "Text-book of Zoology," two vol- 

umes, New York, 1886. 

19. Gegenbaur. — " Elements of Comparative Anatomy," Lon- 

don, 1878. 

20. Huxley. — " A Manual of the Anatomy of Vertebrated Ani- 

mals," New York, 1883. 

21. Huxley. — "A Manual of the Anatomy of Invertebrated 

Animals," New York, 1883. 

22. Lang. — "Text -Book of Comparative Anatomy," Part I., 

New York, 1891. 
22a. Morgan. — "Animal Biology," London, 1889. 

23. Orton. — " Comparative Zoology," New York, 1882. 

24. Packard. — " Zoology for High-Schools and Colleges," New 

York, 1889. 

25. Rolleston and Jackson. — " Forms of Animal Life," Oxford, 

1888. 

26. "Standard Natural History," six volumes, Boston, 1885. 

27. Thompson. — " Outlines of Zoology," New York, 1892. 



396 APPENDIX 

GENERAL WORKS ON BOTANY 

28. Bessey. — "Botany for High - Schools and Colleges," New 

York, 1889. 

29. Bower and Vines. — See No. 3 this list. 

30. Campbell. — " Elements of Structural and Systematic Bot- 

any," Boston, 1890. 

31. Goebel. — " Outlines of Classification and of Special Mor- 

phology of Plants," Oxford, 1887. 

32. Goodale. — See No. 8 this list. 

33. Gray.—" Structural Botany," New York, 1880. 

34. Sachs.—" Text-Book of Botany," Oxford, 1886. 

35. Sachs. — " Lectures on the Physiology of Plants," Oxford, 

1887. 

36. Strasburger. — See No. 15 this list. 

37. Vines. — "Lectures on the Physiology of Plants," Cam- 

bridge, 1886. 

PROTOZOA 

38. Claus and Sedgwick. — See No. 18 this list, vol. i. 

39. Huxley.— See No. 21 this list. 

40. Kent.— " Manual of the Infusoria," London, 1880. 

41. Lang. — See No. 22 this list. 

42. Lankester. — Article " Protozoa," in " Encyclopaedia Britan- 

nica," Ninth edition. Reprinted in "Zoological Ar- 
ticles," New York, 1892. 
42a. Morgan. — See No. 22a this list. 

43. Packard. — See No. 24 this list. 

44. Parker. — "Lessons in Elementary Biology," New York, 

1893. 

45. Rolleston and Jackson. — See No. 25 this list. 

46. " Standard Natural History." — See No. 26 this list, vol. i. 

47. Thompson.— See No. 27 this list. 

AM03BA 

48. Brooks. — "Hand-book of Invertebrate Zoology," Boston, 

1882. 



WORKS OF REFERENCE 397 

49. Bumpus. — " A Laboratory Course of Invertebrate Zoology," 

Providence, 1892. 

50. Claus and Sedgwick. — See No. 18 this list, vol. i. 

51. Davis.—" A Text-book of Biology," Philadelphia, 1888. 

52. Foster. — "A Text-book of Physiology," five volumes, Sixth 

edition, New York, 1893. Introduction. 

53. Griffiths. — " Physiology of the Invertebrata," London, 1892. 

54. Howes. — See No. 9 this list. 

55. Huxley.— See No. 21 this list. 

56. Huxley. — Lecture on a " Piece of Chalk " in "Lay Sermons, 

Addresses, and Reviews," New York, 1871. Also Lect- 
ure on " The Physical Basis of Life," in same. 

57. Huxley and Martin. — See No. 10 this list. 

58. Lang.— See No. 22 this list. 

59. Lankester. — See No. 42 this list. 

60. Leidy. — "Fresh -water Rhizopods of North America," in 

" IT. S. Geological Survey of the Territories," vol. xii., 
Washington, 1879. 

61. Marshall and Hurst.— See No. 12 this list. 
61a. Morgan. — See No. 22a this list. 

62. Packard.— See No. 24 this list. 

63. Parker. — See No. 44 this list. 

64. Rolleston and Jackson. — See No. 25 this list. 

65. " Standard Natural History." — See No. 26 this list, vol. i. 

66. Thompson.— See No. 27 this list. 

PARAMECIUM 

67. Brooks.— See No. 48 this list. 

68. Bumpus. — See No. 49 this list. 

69. Claus and Sedgwick. — See No. 18 this list. 

70. Huxley. — See No. 21 this list. 

71. Kent.— See No. 40 this list. 

72. Lang. — See No. 22 this list. 

73. Lankester. — See No. 42 this list. 

74. Marshall and Hurst. — See No. 12 this list. 
74a. Morgan. — See No. 22a this list. 

75. Packard.— See No. 24 this list. 



398 APPENDIX 

76. Parker. — See No. 44 this list. 

11. Rolleston and Jackson. — See No. 25 this list. 

78. "Standard Natural History." — See No. 26 this list, vol. i. 

79. Thompson. — See No. 27 this list. 

VORTICELLA 

(Same as for " Paramecium ") also 

80. Davis.— See No. 51 this list. 

81. Howes. — See No. 9 this list. 

82. Huxley and Martin. — See No. 10 this list. 

SALIVARY CORPUSCLES 

83. Foster.— See No. 52 this list. 

84. Landois and Stirling. — " Text-book of Human Physiolo- 

gy," Philadelphia, 1889. 

85. Schafer.— See No. 14 this list. 

BLOOD CORPUSCLES 

86. Davis. — See No. 51 this list. 

87. Foster. — See No. 52 this list. 

88. Howes. — See No. 9 this list. 

89. Huxley and Martin. — See No. 10 this list. 

90. Landois and Stirling. — See No. 84 this list. 

91. Marshall.— " The Frog," Fourth edition, London, 1891, 
91a. Morgan. — See No. 22a this list. 

92. Schafer.— See No. 14 this list. 

CILIATED CELLS 

93. Davis. — See No. 51 this list. 

94. Foster.— See No. 62 this list. 

95. Howes. — See No. 9 this list. 

96. Huxley and Martin. — See No. 10 this list. 

97. Landois and Stirling. — See No. 84 this list. 

98. Lang.— See No. 22 this list. 

99. Marshall.— See No. 91 this list. 
100. Schafer.— See No. 14 this list. 



WORKS OF REFERENCE 399 

YEAST 

101. Davis. — See No. 51 this list. 

102. De Bary. — "Lectures on Bacteria," Oxford, 1887. 

103. De Bary. — "Comparative Morphology and Biology of 

Fungi, Mycetozoa, and Bacteria," Oxford, 1887. 

104. Howes. — See No. 9 this list. 

105. Huxley. — Lecture on "Yeast" in "Critiques and Ad- 

dresses," New York, 1873. 

106. Huxley and Martin. — See No. 10 this list. 

107. Parker. — See No. 44 this list. 

108. Pasteur. — "Studies on Fermentation," London, 1879. 

109. Schiitzenberger. — " Fermentation," in " International Scien- 

tific Series," New York, 1876. 

110. Trouessart. — "Microbes, Ferments, and Moulds," in "In- 

ternational Scientific Series," New York, 1886. 

111. Woodhead. — "Bacteria and their Products," New York, 

1891. 

GREEN SLIME 

112. Arthur, Barnes, and Coulter. — "Hand-book of Plant Dis- 

section," New York, 1886. 

113. Davis.— See No. 51 this list. 

114. Goebel.— See No. 31 this list. 

115. Howes. — See No. 9 this list. 

116. Huxley and Martin. — See No. 10 this list. 

117. Parker.— See No. 44 this list. 

118. Sachs.— See No. 34 this list. 

SPORES OF FUNGI 

119. Cooke and Berkeley. — "-Fungi," in "International Scien- 

tific Series," New York, 1880. 

120. De Bary.— -See No. 103 this list. 

121. Goebel.— See No. 31 this list. 

POLLEN-GRAINS 

122. Bower and Vines. — See No. 3 this list 

123. Campbell.— See No. 30 this list. 



400 APPENDIX 

124. Sachs.— See No. 35 this list. 

125. Strasburger. — See No. 15 this list. 

SPIKOGYRA 

126. Arthur, Barnes, and Coulter. — See No. 112 this list. 

127. Bower and Vines. — See No. 3 this list. 

128. Campbell. — See No. 30 this list. 

129. Cooke. — " Introduction to Fresh-water Algse," in " Interna- 

tional Scientific Series," London, 1890. 

130. Davis.— See No. 51 this list. 

131. Goebel.— See No. 31 this list. 

132. Howes.— See No. 9 this list. 

133. Huxley and Martin. — See No. 10 this list. 

134. Parker. — See No. 44 this list. 

135. Sachs.— See No. 34 this list. 

136. Strasburger. — See No. 15 this list. 

137. Wolle.— " Fresh-water Algae of the United States," Beth- 

lehem, Pa., 1887. 

SPONGES 

138. Brooks.— See No. 48 this list. 

139. Bumpus. — See No. 49 this list. 

140. Claus and Sedgwick. — See No. 18 this list, vol. i. 

141. Griffiths.— See No. 53 this list. 

142. Huxley.— See No. 21 this list. 

143. Hyatt. — " Commercial and other Sponges," in " Guides for 

Science Teaching," No. Ill, Boston, 1883. 

144. Lang. — See No. 22 this list. 

145. Sollas. — Article " Sponges," in " Encyclopaedia Britannica," 

Ninth edition. Republished in "Zoological Articles." 
See No. 42 this list. 

146. " Standard Natural History."— See No. 26 this list, vol. i. 

HYDEA 

147. Claus and Sedgwick. — See No. 18 this list, vol. i. 

148. Davis. — See No. 51 this list. 

149. Gegenbaur. — See No. 19 this list. 



WORKS OF REFERENCE 401 

150. Griffiths.— See No. 53 this list. 

151. Howes. — See No. 9 this list. 

152. Huxley. — " On Corals and Coral Reefs," in ■" Critiques and 

Addresses," New York, 1873. 

153. Huxley.— See No. 21 this list. 

154. Huxley and Martin. — See No. 10 this list. 

155. Hyatt. — "Common Hydroids, Corals, and Echinoderms," 

in "Guides for Science Teaching," No. V., Boston, 1875. 

156. Lankester. — Article " Hydrozoa," in " Encyclopaedia Britan- 

nica," Ninth edition. Republished in " Zoological Ar- 
ticles." See No. 42 this list. 

157. Marshall and Hurst. — See No. 12 this list. 
157a. Morgan. — See No. 22a this list. 

158. Parker.— See No. 44 this list. 

159. " Standard Natural History." — See No. 26 this list, vol. i. 

CAMPANULARIAN HYDROID 

160. Agassiz, Mrs. — "A First Lesson in Natural History," in 

"Guides for Science Teaching," No. IV., Boston, 1886. 

161. Brooks.— See No. 48 this list. 

162. Bumpus.— See No. 49 this list. 

163. Claus and Sedgwick. — See No. 18 this list, vol. i. 

164. Gegenbaur. — See No. 19 this list. 

165. Griffiths.— See No. 53 this list. 

166. Huxley. — See No. 21 this list. 

167. Hyatt.— See No. 155 this list. 

168. Lang.— See No. 22 this list. 

169. Lankester. — See No. 156 this list. 

170. Parker. — See No. 44 this list. 

171. " Standard Natural History."— See No. 26 this list, vol. i. 

STARFISH 

172. Agassiz, Mrs.— See No. 160 this list. 

173. Brooks.— See No. 48 this list. 

174. Bumpus. — See No. 49 this list. 

175. Claus and Sedgwick. — See No. 18 this list, vol. i. 

26 



402 APPENDIX 

176. Gegenbaur. — See No. 19 this list. 

177. Griffiths.— See No. 53 this list. 

178. Huxley.— See No. 21 this list. 

179. Hyatt.— See No. 155 this list. 

180. Parker. — See No. 44 this list. 

181. Romanes. — "Jelly-fish, Starfish, and Sea-urchin," in "In- 

ternational Scientific Series," New York, 1885. 

182. " Standard Natural History."— See No. 26 this list, vol. i. 

EARTHWORM 

183. Brooks.— See No. 48 this list. 

184. Claus and Sedgwick. — See No. 18 this list, vol. i. 

185. Darwin. — "Formation of Vegetable Mould through the 

Action of Earthworms," New York, 1881. 

186. Davis.— See No. 51 this list. 

187. Gegenbaur. — See No. 19 this list. 

188. Griffiths.— See No. 53 this list. 

189. Howes. — See No. 9 this list. 

190. Huxley and Martin. — See No. 10 this list. 

191. Hyatt. — " Worms and Crustacea," in " Guides for Science 

Teaching," No. VIL, Boston, 1885. 

192. Lang. — See No. 22 this list. 

193. Marshall and Hurst. — See No. 12 this list. 
193a. Morgan. — See No. 22a this list. 

194. Packard.— See No. 24 this list. 

195. Sedgwick and Wilson. — " General Biology," Part I., New 

York, 1886. 

196. "Standard Natural History."— See No. 26 this list, vol. i. 

LOBSTER 

197. Brooks.— See No. 48 this list. 

198. Bumpus.— See No. 49 this list. 

199. Claus and Sedgwick. — See No. 18 this list, vol. i. 

200. Davis. — See No. 51 this list. 

201. Gegenbaur. — See No. 19 this list. 

202. Griffiths.— See No. 53 this list. 



WORKS OF REFERENCE 403 

203. Howes.— See No. 9 this list. 

204. Huxley. — "The Crayfish," in "International Scientific 

Series," New York, 1880. 

205. Huxley.— See No. 21 this list. 

206. Huxley and Martin.— See No. 10 this list. 

207. Hyatt.— See No. 191 this list. 

208. Lang.— See No. 22 this list. 

209. Marshall and Hurst. — See No. 12 this list. 
209a. Morgan. — See No. 22a this list. 

210. Packard.— See No. 24 this list. 

211. Parker.— See No. 44 this list. 

212. "Standard Natural History."— See No. 26 this list, vol. ii. 

213. Woodward. — Article "Crustacea," in "Encyclopaedia Bri- 

tannica," Ninth edition. 

LOCUST 

214. Brooks. — See No. 48 this list. 

215. Bumpus. — See No. 49 this list. 

216. Claus and Sedgwick. — See No. 18 this list, vol. i. 

217. Comstock. — " Introduction to Entomology," Ithaca, 1888. 

218. Gegenbaur. — See No. 19 this list. 

219. Griffiths.— See No. 53 this list. 

220. Huxley. — See No. 21 this list. 

221. Hyatt and Arms. — "Insecta," in "Guides for Science 

Teaching," No. VIII. , Boston, 1890. 

222. Lang. — See No. 22 this list. 

223. Miall and Denny. — " The Cockroach," London, 1886. 

224. Packard. — " Guide to the Study of Insects," New York, 

1889. 

225. Packard. — See No. 24 this list. 

226. "Reports U. S. Entomological Commission for 1877," 

Washington, 1878. 

227. " Reports U. S. Entomological Commission for 1878 and 

1879," Washington, 1883. 

228. "Reports U. S. Entomological Commission," Washington, 

1883. 

229. "Standard Natural History." — See No. 26 this list, vol. ii. 



404 APPENDIX 

MOLLUSC 

230. Brooks.— " The Oyster," Baltimore, 1891. 

231. Brooks. — See No. 48 this list. 

232. Claus and Sedgwick. — See No. 18 this list, vol. li. 

233. Davis.— See No. 51 this list. 

234. Gegenbaur. — See No. 19 this list. 

235. Griffiths.— See No. 53 this list. 

236. Howes.— See No. 9 this list. 

237. Huxley.— See No. 21 this list. 

238. Huxley and Martin. — See No. 10 this list. 

239. Hyatt. — " Oyster, Clam, and other Common Molluscs," 

in " Guides for Science Teaching," No. TI., Boston, 
1884. 

240. Lankester. — Article " Mollusca," in "Encyclopaedia Britan- 

nica," Ninth edition. Kepublished in " Zoological Ar- 
ticles." See No. 42 this list. 

241. Marshall and Hurst. — See No. 12 this list. 
241a. Morgan.— See No. 22a this list. 

242. Parker. — See No. 44 this list. 

243. " Standard Natural History."— See No. 26 this list, vol. ii. 

244. Tryon. — " Structural and Systematic Conchology," Phil- 

adelphia, 1882. 

245. Woodward.—" Manual of the Mollusca," London, 1890. 



FROG 

246. Claus and Sedgwick. — See No. 18 this list, vol. ii. 

247. Davis. — See No. 51 this list. 

248. Gegenbaur.— See No. 19 this list. 

249. Howes. — See No. 9 this list. 

250. Huxley. — Article "Amphibia," in "Encyclopaedia Britan- 

nica," Ninth edition. 

251. Huxley.— See No. 20 this list. 

252. Huxley and Martin.— See No. 10 this list. 

253. Lankester. — Article " Vertebrata," in " Encyclopaedia Bri- 

tannica," Ninth edition. Republished in "Zoological 
Articles." See No. 42 this list. 



WORKS OF REFERENCE 405 

254. Marshall. — "The Frog," Fourth edition, London, 1891. 

255. Mivart.— " The Common Frog," London, 1874. 
255a. Morgan. — See No. 22a this list. 

256. Owen. — " Comparative Anatomy and Physiology of Verte- 

brata," London, 1868. 

257. Packard.— See No. 24 this list. 

258. " Standard Natural History." — See No. 26 this list, vol. iii. 

259. Wiedersheim. — "Elements of the Comparative Anatomy 

of Vertebrates," New York, 1886. 

VAUCHERIA 

260. Bower and Vines. — See No. 3 this list. 

261. Campbell.— See No. 30 this list. 

262. Cooke.— See No. 129 this list. 

263. Goebel.— See No. 31 this list. 

264. Parker.— See No. 44 this list. 

265. Sachs.— See No. 34 this list. 

266. Strasburger. — See No. 15 this list. 

267. Wolle.— See No. 137 this list. 

CHARA 

268. Bower and Vines. — See No. 3 this list. 

269. Campbell.— See No. 30 this list. 

270. Davis. — See No. 51 this list. 

271. Goebel.— See No. 31 this list. 

272. Howes. — See No. 9 this list. 

273. Huxley and Martin. — See No. 10 this list. 

274. Parker. — See No. 44 this list. 

275. Sachs.— See No. 34 this list. 

276. Strasburger. — See No. 15 this list. 

ROCKWEED 

277. Bessey.— See No. 28 this list. 

278. Bower and Vines. — See No. 3 this list. 

279. Campbell. — See No. 30 this list. 



406 APPENDIX 

280. Davis.— See No. 51 this list. 

281. Goebel. — See No. 31 this list. 

282. Sachs. — See No. 34 this list. 

283. Strasburger.— See No. 15 this list. 

PENICILLITJM 

284. Campbell— See No. 30 this list. 

285. Cooke and Berkeley.— See No. 119 this list. 

286. Davis.— See No. 51 this list. 

287. De Bary.— See No. 103 this list. 

288. Goebel.— See No. 31 this list. 

289. Howes.— See No. 9 this list. 

290. Huxley and Martin. — See No. 10 this list. 

291. Parker.— See No, 44 this list. 

292. Strasburger. — See No. 15 this list. 

AGARICUS 

293. Bower and Vines. — See No. 3 this list. 

294. Campbell.— See No. 30 this list. 

295. De Bary.— See No. 103 this list. 

296. Goebel— See No. 31 this list. 

297. Parker.— See No. 44 this list. 

298. Sachs.— See No. 34 this list. 

299. Strasburger. — See No. 15 this list. 

MARCHANTTA 

300. Arthur, Barnes, and Coulter. — See No. 112 this list. 

301. Bower and Vines. — See No. 3 this list. 

302. Goebel— See No. 31 this list. 

303. Sachs. — See No. 34 this list. 

304. Strasburger. — See No. 15 this list. 

FERN 

305. Arthur, Barnes, and Coulter. — See No. 112 this list. 

306. Bower and Vines. — See No. 3 this list. 



WOEKS OF EEFEEENCE 407 

30V. Campbell— See No. 30 this list. 

308. Davis. — See No. 51 this list. 

309. De Bary. — " Comparative Anatomy of the Vegetative Or- 

gans of Phanerogams and Ferns," Oxford, 1884. 

310. Eaton. — "Ferns of North America," Salem, 1879. 

311. Goebel.— See No. 31 this list. 

312. Howes. — See No. 9 this list. 

313. Huxley and Martin. — See No. 10 this list. 

314. Parker.— See No. 44 this list. 

315. Sachs.— See No. 34 this list. 

316. Sedgwick and Wilson.— See No. 195 this list. 

THE ELOWEEING PLANT 

317. Allen.— " Colors of Flowers," London, 1882. 

318. Arthur, Barnes, and Coulter. — See No. 112 this list. 

319. Bessey.— See No. 28 this list. 

320. Bower and Vines. — See No. 3 this list. 

321. Campbell.— See No. 30 this list. 

322. Darwin. — "Different Forms of Flowers on Plants of the 

Same Species," New York, 1891. 

323. Darwin. — "On the Effects of Self and Cross Fertilization 

in the Vegetable Kingdom," New York, 1891. 

324. Darwin. — "Power of Movement in Plants," New York, 

1888. 

325. Darwin. — "Movements and Habits of Climbing Plants," 

New York, 1876. 

326. Davis. — See No. 51 this list. 

327. De Bary. — See No. 309 this list. 

328. Goebel.— See No. 31 this list. 

329. Goodale. — See No. 8 this list. 

330. Gray. — See No. 33 this list. 

331. Henslow. — "Origin of Floral Structures," in "Interna- 

tional Scientific Series," New York, 1888. 

332. Howes. — See No. 9 this list, 

333. Huxley and Martin.— See No. 10 this list. 

334. Kerner. — " Flowers and their Unbidden Guests," London, 

1882. 



408 APPENDIX 

335. Lubbock. — " On Flowers and Insects," in " Scientific Lect- 

ures," London, 1879. 

336. Lubbock. — "British Wild Flowers Considered in their 

Relation to Insects," London, 1875. 

337. Lubbock. — "Flowers, Fruits, and Leaves," London, 1886. 

338. Miiller. — "Fertilization of Flowers," New York, 1886. 

339. Parker. — See No. 44 this list. 

340. Sachs. — See No. 34 this list. 

341. Sachs. — See No. 35 this list. 

342. Vines. — See No. 37 this list. 



THEORIES OF EVOLUTION, HEREDITY, ETC. 

343. Beddard. — "Animal Coloration," New York, 1892. 

344. Ball.— "Are the Effects of Use and Disuse Inherited?" 

New York, 1890. 

345. Conn.— " Evolution of To-Day," New York, 1886. 

346. Conn.—" The Living World," New York, 1891. 

347. Cope.—" Origin of the Fittest," New York, 1887. 

348. Darwin. — "On the Origin of Species," New York, 1891. 

349. Eimer.— " Organic Evolution," New York, 1890. 

350. Geddes and Thompson.—" The Evolution of Sex," New 

York, 1890. 

351. Haeckel. — " The History of Creation," two volumes, Fourth 

edition, New York, 1892. 

352. Heilprin. — " Geographical and Geological Distribution of 

Animals," New York, 1886. 

353. Huxley. — " On the Origin of Species," New York, 1870. 

354. Le Conte. — "Evolution: its Nature, its Evidences, and its 

Relation to Religious Thought," New York, 1891. 

355. Letourneau. — " Biology," London, 1890. 

356. Lubbock. — " Ants, Bees, and Wasps," New York, 1882. 

357. Lubbock. — " On the Senses, Instincts, and Intelligence of 

Animals," New York, 1888. 

358. Poulton.— " The Colors of Animals," New York, 1890. 

359. Romanes. — " Animal Intelligence," New York, 1883. 

360. Romanes. — " Darwin and After Darwin," Part I., "The 

Darwinian Theory," Chicago, 1892. 



WORKS OF REFERENCE 409 

361. Romanes. — "Scientific Evidences of Organic Evolution," 

London, 1882. 

362. Romanes. — "An Examination of Weismannism," Chicago, 

1893. 

363. Schmidt. — " The Doctrine of Descent and Darwinism," 

New York, 1878. 

364. Semper. — "Animal Life as Affected by the Natural Con- 

ditions of Existence," New York, 1881. 

365. Spencer. — "The Principles of Biology," two volumes, 

New York, 1866. 

366. Thompson.—" The Study of Animal Life," New York, 

1892. 

367. Wallace. — "On Natural Selection," London, 1870. 

368. Wallace.— " Darwinism," New York, 1891. 

369. Weismann. — " Essays upon Heredity and Kindred Biolog- 

ical Problems," Oxford, 1891 and 1892. 

370. Weismann.— " The Germ Plasm," New York, 1893. 



INDEX AND GLOSSAKY 



[In preparing the glossary it has been thought advisable to omit the Greek and Latin 
words from which the various biological terms are derived. This has been done partly 
to save space and partly for the reason that most students in scientific courses are not 
familiar with the classical languages, especially with the Greek. The English equivalents 
of such words are given, and in most cases define the term with sufficient accuracy.] 



Abdo'men, Lobster, 140; Locust, 178 ; 

Mussel, 196. 
Acetabulum (L. vinegar cup), Frog, 

219. 
Adipose tissue, Frog, 259. 
Adrenal body, Frog, 234. 
Agar' ices {Gr. from Agari, a people 

of Sarmatia), 301 ; spores of, 46. 

See Mould. 
Air-sacs, Locust, 183. 
Albumen, tests for, Seeds, 340. 
Alcohol, formation of, in yeast, 36. 
Aleu'rone (Gr. fine flour), microscopic 

examination of, Seeds, 341 ; tests 

for, Seeds, 340. 
Alimentary canal, Frog, 229. 
Ambula'cral (L. walk) feet, Starfish, 

103 ; grooves, 103 ; ossicles, 105 ; 

pores, 105. 
Amce'ba (Gr. change), 6. See Pro- 
teus Animalcule. 
Am'phidiscs (Gr. at both ends, a 

round plate), Sponge, 72. 
Ampul'la, pi. ampullae (L. a water 

bottle), Frog, 257 ; Starfish, 109. 
Andrce'cium (Gr. male dwelling), 

Flowers, 373. 



Animal Cell, Morphology and Physi- 
ology, 3. 

Animals, The Unicellular, 3. 

Annual rings, Stem, 351. 

Annulus, Fern, 333 ; Mushroom, 302, 
303. 

Anodon'ta (Gr. without teeth), 189. 
See Fresh-water Mussel. 

Antebra'chium (L. before, arm), Frog, 
208, 217. 

Anten'na, pi. antennae, dim. antennule 
(L. a sail yard), Lobster, 148 ; Lo- 
cust, 174. 

Antherid'ium, pi. antheridia {Gr. 
flower), Fern, 234 ; Green Felt, 270 ; 
Liverwort, 309, 316; Eockweed, 
294; Stonewort, 278. 

An'therozoid (Gr. flower, animal, 
form), Fern, 334 ; Green Felt, 270 ; 
Liverwort, 316 ; Rockweed, 294. 

An'thotaxy {Gr. flower, order), Flow- 
ering Plant, 370. 

Aorta, Frog, 242; Mussel, 199. 

Aortic arches, Frog, 237, 241, 242. 

Apical cell, Fern, 327, 328; Rock- 
weed, 281 ; Stonewort, 281. 

Aponeurosis {Gr. becoming a ten- 
don). 

Apparatus, xviii. 



412 



INDEX AND GLOSSARY 



Appendages, Lobster, 141. 
Aqueduct of Sylvius, Frog, 248. 
Archego'uiuin, p>l. archegonia (Gr. 

first of a race), Liverwort, 310, 317. 
Areolar tissue, Frog, 259. 
Arteries, Frog, 241. 
Arthrobran'chia, pi. arthrobranchise 

(Gr. joint, gill), Lobster, 150. 
Ascospores, Mould, 300. 
As'cus, pi. asci (Gr. a sac), Mould, 

300. 
Aspid'ium (Or. a little shield), 320. 

See Fern. 
Assimila'tion (L. to make similar), 

Leaves, 368 ; Spirogyra, 58. 
As'tacus (Gr. a crawfish), 138. See 

Lobster. 
Aste'rias (Gr. a star), 9V. See Star- 
fish. 
Auditory capsule, Frog, 219; nerve, 

Frog, 255, 257; sac, Lobster, 152. 
Auricle, Frog, 237, 244 ; Lobster, 157. 
Automatic'ity (Gr. acting of one's 

own will), Slipper Animalcule, 16. 

B 

Basidiospore, Mushroom, 306. 

Basid'ium, pi. basidia (Gr. a little 
base), Mushroom, 306. 

Bast, Fern, 330; parenchyma, Fern, 
330. 

Bean, 336. 

Beat of the heart, Frog, 262. 

Bell Animalcule, 18 ; ciliary move- 
ment, 20; encystation, 20; myo- 
phan layer, 19; peristome, 19. 

Biology of the Animal, 63-263 ; op 
the Cell, 1-61 ; of the Plant, 265- 
377. 

Bladder, Frog, 234. 

Blas'tostyle (Or. a germ, pillar), Hy- 
droid, 94. 

Blood Cells, 23. 

Blood, Earthworm, 131; Lobster, 159. 

Bojanus, organ of, Mussel, 301. 

Brach'ium (L. the arm), Frog, 208, 
217. 



Brain, Earthworm, 132 ; Frog, 246, 
247 ; Lobster, 164 ; Locust, 184. 

Branchios'tegite (Gr. gills, a cover- 
ing), Lobster, 143. 

Bron'chus (Gr. the windpipe), Frog, 
233. 

Budding, the asexual production of 
new individuals by the formation 
of an outgrowth from the body of 
the parent, Yeast, 38. 

Buds, 358. 

Bud-scales, 360. 

Bundle-sheath, Fern, 330. 



Calopte'nus (Gr. beautiful - winged), 
172. See Locust. 

Ca'lyx (Gr. the cup of a flower), 
Flowers, 371. 

Cambium, Stems, 352. 

Campanula'ria (L. a little bell), 90. 
See Campanula rian Hydroid. 

Campanularian Hydroid, 90 ; general 
structure, 91; physiology, 94; zo- 
oids, 92. 

Capit'ulum, pi. capitula (L. a little 
head), Stonewort, 279. 

Cartilage corpuscles, Frog, 259. 

Cau'da equi'na (L. mare's tail), Frog, 
250. 

Caul'icle (L. a little stalk), Seeds, 
337. 

Cavity, segmentation, Starfish, 119. 

Cell, Animal, Morphology and Phys- 
iology, 3 ; Plant, Moiphology and 
Physiology, 28 ; Biology of, 1. 

Cell-formation, Spirogyra, 60. 

Cells, amoeboid, Starfish, 120; ciliated, 
26 ; direction, Starfish, 117; inter- 
stitial, Hydra, 87 ; structure of sex- 
ual, Starfish, 116. 

Cellulose, tests for, 43. 

Central nervous system, Frog, 247. 

Cephalic plates, Locust, 174. 

Cephaliza'tion, the tendency to local- 
ization of important parts (e. g. 
sense organs, organs of locomotion 



INDEX AND GLOSSARY 



413 



in certain crustaceans, etc.) near 
the head. 

Cephalotho'rax (Gr. head, a breast- 
plate), Lobster, 142. 

Cerebellum (L. a little brain), Frog, 
248. 

Cerebral hemispheres, Frog, 247. 

Cerebro-spinal canal, Frog, 246. 

Cha'ra ( Gr. delight), 273. See Stone- 
wort. 

Che'la (Gr. a claw), Lobster, 146. 

Chemical composition of ossicles, Star- 
fish, 106. 

Chemical contents of dry seeds, 338 ; 
of germinating seeds, 346. 

Chias'ma (Gr. marked with two 
crossed lines like the letter X), 
Frog, 249. 

Chlo'rophyll (Gr. green leaf), bodies, 
Frog, 269 ; Green Slime, 43 ; Water 
Silk, 54. 

Cho'roid (Or. membrane, form), plex- 
us (L. a net-work), Frog, 246. 

Chro'matophores (Gr. color bearing), 
Frog, 269. See Chlorophyll Bodies. 

Ciliary action, Mussel, 197 ; move- 
ment, Bell Animalcule, 20. 

Ciliated Cells, 26. 

Cil'ium, pi. cilia (Z. an eyelid), Frog, 
270; Slipper Animalcule, 13; of 
antherozoid, Fern, 334. 

Cin'gulum (L. a girdle), Earthworm, 
125. 

Circulation, Earthworm, 137. 

Circulatory system, Earthworm, 131 ; 
Frog, 236; Lobster, 156; Mussel, 
199; Starfish, 110. 

Clavicle (X. a small key), Frog, 212. 

Clitel'lum (L. a pack-saddle), Earth- 
worm, 125. 

Cloa'ca (L. a sewer), Frog, 231 ; Gran- 
tia, 76. 

Cni'doblast (Gr. a nettle, germ), Hy- 
dra, 87. 

Cni'docil, Hydra, 87. 

Coe'cum, pi. coeca (L. a blind pouch), 
hepatic, Starfish, 107. 



Cce'lom (Gr. a cavity), Starfish, 106. 

Coe'nosarc (Gr. common, flesh), Hy- 
droid, 92. 

Columella, Pond Snail, 193. 

Column, vertebral, Frog, 209. 

Com'missure (L. to join), a nerve cord 
which connects ganglia on one side 
with corresponding ganglia on the 
opposite side of the body. See Con- 
nective. 

Concep'tacles (L. to contain), Rock- 
weed, 293. 

Con'dyle (Gr. a knob), Frog, 212. 

Conid'iophore (Gr. conidium, bearing), 
Mould, 298, 299. 

Conidlum, pi. conidia (Gr. dust, fine), 
Mould, 299. 

Conjugation (L. a coupling), the union 
of two cells in sexual reproduc- 
tion. 

Connective, a nerve cord which con- 
nects ganglia on the same side of 
the body, Mussel, 200. See Com- 
missure. 

Connective tissue, Frog, 220 ; corpus- 
cles, Frog, 259. 

Contractile vacuole, Proteus Animal- 
cule, 8; Slipper Animalcule, 12. 

Contractility (L. a drawing together), 
the inherent property of protoplasm 
of contracting when stimulated. 

Co-ordination (L. to arrange together), 
the normal and harmonious regula- 
tion of bodily functions. Hydra, 86; 
Slipper Animalcule, 16; Starfish, 
114. 

Cork-layer, Stems, 353. 

Corolla (L. a little crown), Flowers, 
372. 

Cortical cells, Stonewort, 277. 

Cranial nerves, Frog, 253. 

Cra'nium (Gr. the skull), Frog, 211. 

Crayfish, 138. See Lobster. 

Ci-us (L. the leg), Frog, 208, 219. 

Crystalline lens of eye, Frog, 256. 

Cu'pule (L. a little cup), Liverwort, 
310, 313. 



414 



INDEX AND GLOSSARY 



Cutaneous glands, Frog, 258. 
Cystic ducts, Frog, 231. 

D 

Development o'f prothallium, Fern, 
335. 

Diastase of malt, action of, upon 
starch, 347. 

Dias'tole (Gr. expansion). See Sys- 
tole. 

Differentia' tion, the evolutionary proc- 

. ess by which originally similar 
parts become specialized in struct- 
ure or function. 

Digestive system, Earthworm, 129; 
Frog, 227; Lobster, 159; Locust, 
181; Mussel, 198; Starfish, 107. 

Direct observation of the ascent of 
water in stems, 356. 

Dissection, Rules for, xviii. 

Division, a non-sexual method of pro- 
ducing new cells or organisms by 
the separation of the parent cell or 
organism into two more or less sim- 
ilar parts. Same as Fission. 

Drawing, xx. 

Du ode' num. (L. twelve each), Frog, 
231. 

Du'ra ma'ter (Z. hard mother), Frog, 

247. 

E 

Earthworm, 122; blood, 131; brain, 
132; capsulogenous glands, 127; 
circulatory system, 131 ; cuticle, 
125; digestive system, 129; excre- 
tory system, 133 ; exoskeleton, 124 ; 
feeding, 136; movements, 135; 
nephridia, 133; nervous system, 
132; oesophageal glands, 130; re- 
productive system, 133 ; segmental 
organs, 133; segments, 122; setae, 
125 ; spermathecas, 134 ; supra- 
cesophageal ganglion, 132 ; testes, 
134; ventral ganglia, 132. 

Ectoderm (Gr. outside skin), Hy- 
droid, 86 ; Starfish (egg), 120. 

Ec'tosarc (Gr. outside flesh), Proteus 



Animalcule, 7 ; Slipper Animalcule, 
12. 

Embryo, Seeds, 337. 

Embryo-sac, Flowers, 376. 

Enceph'alon (Gr. the brain), Frog, 
246. 

Encysta'tion, a resting condition, usu- 
ally preparatory to reproduction, as- 
sumed by some of the lower organ- 
isms, e. g. Protozoa, during which 
they are enclosed in a sac or cyst. 

Endogenous spore formation, Yeast, 
38. 

Endophragmal system, Lobster, 164. 

En'dosarc (Gr. inside flesh), Proteus 
Animalcule, 7 ; Slipper Animalcule, 
12. 

Enlargements of spinal cord, Frog, 250. 

En'teron (Gr. the intestine), Hydroid, 
86. 

En'toderm (Gr. inside skin), Hydroid, 
86; Starfish (egg), 120. 

Epidermis, Liverwort, 311; Lobster, 
153; Mussel, 190; Stems, 353. 

Euro'tium (Gr. mould), spores of, 46. 
See Mould. 

Euspongia ( Gr. well, sponge), 65. See 
Sponges. 

Excretory system, Earthworm, 133 ; 
Lobster, 163 ; Mussel, 201. 

External anatomy of the heart, Frog, 
237. 

Eye, Frog, 256; Lobster, 151 ; Locust, 
*174; Starfish, 104. 

F 

Feeding, Earthworm, 136 ; Hydra, 95; 
Lobster, 167. 

Fern, 320 ; antheridia, 334 ; apical 
cells, 327, 328; archegonia, 334; 
bast, 330; bundle-sheath, 326, 330; 
capsule, 333 ; cilia, 334 ; develop- 
ment of prothallium, 335; epider- 
mis, 325; fib ro -vascular bundle, 
325, 326, 330; fronds, 321, 324, 
329; germination of spore, 131; 
growing point, 327, 334 ; indusium, 



INDEX AND GLOSSARY 



415 



322, 332; internodes, 322; meris- 
tern, 329; mesophvll, 331 ; nodes, 
322 ; oosphere, 335 ; parenchyma, 
325, 326 ; phloem, 326, 330 ; pinna, 
321, 331 ; prothallium, 333 ; rachis, 

321, 329; rhizoids, 334; rhizome, 

322, 325 ; root, 328 ; root-cap, 324, 
329; root-hairs, 323,328; scleren- 
chyina, 325, 326; segmental cells, 

329 ; sexual generation, 333 ; sieve- 
tubes, 330 ; sori, 322 ; sporangia, 
322, 332; stomata, 332; tracheids, 
327, 330; trichomes, 329; wood, 

330 ; xylem, 326, 330. 
Fertilization, Flowers, 376 ; Rock- 
weed, 295; Starfish, 118; of oo- 
sphere, Liverwort, 318. 

Fission. See Division. 

Flagel'lum, pi. flagella (L. a whip), 
Stonewort, 280. 

Flowering Plant, 336 ; buds, 358 ; 
flowers, 369 ; leaves, 362 ; roots, 
357; seeds, 336; stems, 348. 

Flowers, 369 ; andrcecium, 373 ; ca- 
lyx, 371 ; corolla, 372 ; embryo-sac, 
376 ; funiculus, 376 ; gynaecium, 
374 ; micropyles, 376 ; ovary, 374 ; 
pedicel, 371; petals, 372; pistil, 
374; stamens, 373. 

Food-vacuoles, Slipper Animalcule, 
14, 15. 

Fora'men (L. a hole). 

Fresh -water Mussel, 189; beak, 
191 ; cerebral ganglia, 200; ciliary 
action, 197 ; circulatory system, 
199; digestive system, 198; epi- 
dermis, 190 ; excretory system, 201 ; 
generative gland, 198; gills, 196; 
heart, 199; inter-cerebral commis- 
sure, 200; kidney, 201 ; liver, 198; 
mantle, 194; nervous system, 200; 
organ of Bojanus, 201 ; otocysts, 
201 ; pallium, 194 ; pericardium, 
199; siphons, 195; soft parts, 194; 
umbo, 191 ; ureter, 201. 

Fresh- water Polyp, 80 ; cnidoblasts, 
87 ; contractility, 83 ; co - ordina- 



tion, 86 ; disk, 82 ; ectoderm, 86 
enteron, 86 ; entoderm, 86 ; hypo 
stome, 83 ; interstitial cells, 87 
irritability, 85 ; locomotion, 83 
movements, 83 ; nematocysts, 87 
nervous properties, 85 ; nutrition 
85 ; ovaries, 88 ; tentacles, 83 
testes, 88. 

Fresh- water Sponge, 68 ; flagellate 
cells, 71 ; spicules, 71. 

Frog, 203 ; adipose tissue, 259 ; ali- 
mentary canal, 229 ; aortic arches, 
237, 241, 242; aqueduct of Syl- 
vius, 248 ; areolar tissue, 259 ; ar- 
teries, 241 ; auditory nerve, 255, 
257 ; auricle, 237, 244 ; axial skel- 
eton, 209 ; beat of the heart, 262 ; 
bladder, 234; brain, 246, 247; 
bronchus, 233 ; carotid gland, 242 ; 
cartilage corpuscles, 259 ; cauda 
equina, 250 ; central nervous sys- 
tem, 24-7; cerebellum, 248 ; cerebral 
hemispheres, 247; cerebro- spinal 
canal, 246 ; choroid plexus, 246 ; 
circulation, 262 ; circulatory sys- 
tem, 199, 236; connective tissue, 
220, 258 ; cranial nerves, 253 ; cra- 
nium, 211; crus, 208, 219; cuta- 
neous glands, 258 ; cystic ducts, 
231 ; digestive system, 227 ; dura 
mater, 247 ; ear, 257 ; encephalon, 
246 ; enlargements of spinal cord, 
250; external anatomy of the heart, 
237 ; eye, 256 ; fat bodies, 235 ; fat 
cells, 259; fibrous tissue, 258 ; filum 
terminate, 250 ; foramen magnum, 
212 ; foramen of Monro, 249 ; fore 
limb, 217 ; fourth ventricle of brain, 
248; gall-bladder, 231; Gasserian 
ganglion, 254 ; glottis, 228 ; hepatic 
cells, 261; hip-girdle, 209; hyaline 
cartilage, 259; hyoid apparatus, 215 ; 
hypophysis, 250; infundibulum, 249; 
internal anatomy of the heart, 243 ; 
intestine, 230; kidneys, 234; larynx, 
232 ; lateral ventricles of brain, 249 ; 
limb - girdles, 209; liver, 229, 260; 



416 



INDEX AND GLOSSAEY 



lungs, 233; lymph, 220; lymph 
hearts, 245 ; mandible, 213 ; manus, 
217 ; maxillary teeth, 22V ; Meckel's 
cartilage, 212 ; medulla oblongata, 
248 ; medullated nerve fibres, 260 ; 
mesentery, 230 ; muscular system, 
220 ; muscular tissue, 259 ; myelon, 
246 ; nervous system, 245 ; nervous 
tissue, 260 ; olfactory lobe, 247 ; 
olfactory nerve, 215, 247, 254 ; op- 
tic chiasma, 249 ; optic lobes, 248 ; 
optic nerve, 214, 254, 256 ; optic 
thalami, 248 ; optic tract, 249 ; pan- 
creas, 231 ; pectoral girdle, 209, 
215 ; pelvic girdle, 209, 218; peri- 
cardium, 237 ; perichondrium, 259 ; 
periganglionic glands, 251 ; periph- 
eral nervous system, 251; perito- 
neum, 232; pes, 208; phalanges, 
218 ; pia mater, 246 ; pituitary 
body, 250 ; pylorus, 231 ; respira- 
tory system, 232 ; roots of nerves, 
250; sciatic plexus, 252; semicir- 
cular canals, 257 ; sense capsules, 
212; shoulder girdle, 209; sinus 
venosus, 238 ; skeleton, 209 ; skull, 
209, 211; spermatozoa, 261 ; spinal 
cord, 246, 250 ; spinal nerves, 250, 
251; spleen, 232; sternum, 216; 
stomach, 229 ; sympathetic nervous 
system, 253 ; testis, 235, 261 ; thal- 
amencephalon, 247 ; third ventricle 
of brain, 248 ; tongue, 228 ; truncus 
arteriosus, 237, 244 ; urino-genital 
system, 234; urostyle, 210; veins, 
238; venae cavae, 238; vertebral 
column, 209; vocal cords, 233; 
vocal sac, 229, 233 ; vomerine teeth, 
215, 227. 

Frog-spittle, 51. See Water Silk. 

Fu'cus (Gr. seaweed), 285. See Rock- 
weed. 

G 

Gametan'giura, pi. gametangia (Gr. 
marriage), Green Felt, 270. 

Gan'glion, pi. ganglia ( Gr. a swelling), 
a mass of nerve cells. 



Gas'trolith (Gr. stomach, stone), Lob- 
ster, 161. 

Gas'trula {Gr. stomach), a stage of 
development in which the embryo 
consists of two layers of cells sur- 
rounding a digestive cavity which 
has an external opening; Starfish, 
120. 

Gem'ma, pi. gemmae (L. a swelling 
bud), Liverwort, 310, 313. 

Gemma'tion. See Budding. 

Gemmules, Spongilla, 72. 

Geo'tropism (Gr. the earth, a turn- 
ing), the tendency to grow towards 
the earth ; seedlings, 345 ; Stems, 
355. 

Germination, conidia,' Mould, 300; 
pollen grains, 50 ; Seeds, 344 ; 
spores, Fern, 335 ; spores, Fungi, 
47 ; Yeast, 38. 

Gills, Lobster, 146 ; Mushroom, 302 ; 
Mussel, 196. 

Girdle, Earthworm, 125. 

Gland, calciferous, Earthworm, 130; 
capsulogenous, Earthworm, 127 ; 
digestive, Lobster, 162 ; generative, 
Mussel, 198; green, Lobster, 162; 
oesophageal, Earthworm, 130. 

Gran'tia (L. from Grant, a proper 
name), 73. See Sponges. 

Green Felt, 267; antheridium, 270; 
gametangia, 270; oogonium, 270; 
zoogonidia, 271; zoospores, 271. 

Green Slime, 39 ; cell wall, 43; chro- 
matophores, 43 ; vegetative cells, 
44; zygospores, 44. 

Growing point, Fern, 327, 334; Rock- 
weed, 289. 

Growth, Stonewort, 282 ; Water Silk, 
60. 

Gynae'cium (Gr. female, house), Flow- 
ers, 374. 

H 

Heart, Earthworm, 131; Frog, 207, 
243; Lobster, 157; Locust, 180; 
Mussel, 199; Starfish, 110. 

Helio'tropism (Gr. the sun, a turn- 



INDEX AND GLOSSARY 



417 



ing), the tendency to bend towards 
or away from the light, Hydra, 86 ; 
Stems, 356. 
Hepatic cells, Frog, 261 ; cceca, Star- 
fish, 107. 
Hip-girdle, Frog, 209. 

Hom'arus (Gr. a lobster), 138. See 
Lobster. 

Homol'ogy (Gr. agreement), serial, 
the agreement in structure and 
mode of development between series 
of structures, 137. 

Hyaline cartilage, Frog, 259. 

Hy'dra (Gr. Hydra, a mythological 
serpent which had nine heads), 80. 
See Fresh-water Polyp. 

Hydranths, Hydroid, 91. 

Hy'oid apparatus, Frog, 215. 

Hy'pha, jo£. hyphae (Gr. a web), Mould, 
298. 

Hy'postome (Gr. under mouth), Pol- 
vp, 83. 

I 

Imbibition, Seeds, 342. 

Indu'sium (L. a tunic), Fern, 322, 
332. 

Infundib'ulum (L. a funnel), Frog, 
249. 

Ingestion, Blood Cells, 25; Grantia, 
73. 

Initial cells, Rockweed, 291. 

Internal anatomy of the heart, Frog, 
243. 

Internode, Fern, 322; Stems, 349; 
Stonewort, 275. 

Interstitial cells, Hydra, 86. 

Intestine, Earthworm, 130; Frog, 
230; Lobster, 162; Mussel, 198; 
Starfish, 108. 

Iodine-sulphuric acid test for cellu- 
lose, Green Slime, 44. 

Iodine test for starch, Yeast, 31. 

Irritability (L. easily excited), the in- 
herent property of protoplasmic 
bodies of responding to a stimu- 
lus, Polyp, 83 ; Slipper Animalcule, 
16. 

27 



K 

Kidney, Frog, 234; Lobster, 163; 
Mussel, 201. 

L 

Lamella, pi. lamellae (L. a thin plate), 
Mushroom, 302. 

Lar'ynx (Gr. the upper part of the 
windpipe), Frog, 232. 

Lasso-cells, Hydroid, 93. 

Lateral ventricles of brain, Frog, 249. 

Leaves, 362. 

Limb-girdles, Frog, 209. 

Liver, Frog, 229, 260 ; Lobster, 162 ; 
Mussel, 198 ; Starfish, 107. 

Liverwort, 308 ; antheridia, 309, 316; 
archegonia, 309, 317 ; cupules, 310, 
313; gemmae, 310; receptacle, 310; 
rhizoid, 311, 312 ; sporogonia, 318 ; 
stomata, 313. 

Lobster, 138 ; appendages, 141 ; ar- 
throbranchise, 150; auditory hairs, 
152; branchiostegite, 143; breath- 
ing, 168; carapace, 142; cephaliza- 
tion, 149 ; chela, 146 ; circulatory 
system, 156; cuticle, 150; digestive 
system, 159; ear, 152; endophrag- 
mal system, 164; epidermis, 153; 
excretory system, 163 ; exoskeleton, 
150 ; eye, 151 ; eye-stalk, 149 ; feed- 
ing, 167; gastric ossicles, 160: gas- 
tric teeth, 161; gill, 146; green 
glands, 163; heart, 143, 157; man- 
dible, 148; metameres, 140; micro- 
scropic examination of the blood, 
159; movements, 165; muscular 
system, 153 ; nervous properties, 
169; nervous system, 164; olfac- 
tory setae, 152; optic nerve, 151; 
organs of special sense, 150; oto- 
liths, 152; ovaries, 164; pericar- 
dial sinus, 156 ; pleurobranchiae, 
150; podobranchiae, 150; repro- 
ductive system, 163; segments, 140; 
sight, 169; smell, 169; spermato- 
zoa, 163; sternum, 141; stomach, 
159 ; swimmerets, 141 ; tactile or- 



418 



INDEX AND GLOSSARY 



gans, 151 ; taste, 161 ; telson, 144; 
ureters, 163. 

Locomotion, Frog, 261 ; Hydra, 83. 

Locust, 172; abdomen, 178; abdom- 
inal muscles, 181 ; air-sacs, 183 ; an- 
tennae, 174; cephalic plates, 174; 
digestive system, 181; ear, 178; 
eyes, 174; head, 174; heart, 180; 
mouth parts, 175; nervous system, 
184; ovary, 183; ovipositor, 179; 
salivary glands, 182 ; spiracles, 179 ; 
stigmata, 179; testes, 183; thigh 
muscles, 185; thorax, 176; tongue, 
176; tracheas, 181; wing muscles, 
181. 

Lumbri'cus (L. an earthworm), 122. 
See Earthworm. 

Lungs, Frog, 233. 

Lymnje'us (Gr. a pool), 192. 

M 

Macronu'cleus (Gr. large, L. a kernel), 
Slipper Animalcule, 13. 

Mandible, Frog, 212; Lobster, 148; 
Locust, 176. 

Mantle, Mussel, 194. 

Manu'brium (L. a handle), Hydroid, 
93 ; Stonewort, 279. 

Ma'nus (L. the hand), Frog, 208, 217. 

Marchan'tia (L. named from Mar- 
chant, a French botanist), 308. See 
Liverwort. 

Maxil'la (L. the jaw-bone), Frog, 212; 
Lobster, 148 ; Locust, 176. 

Maxillary teeth, Frog, 228. 

Maxil'lipede (L. jaw, foot), Lobster, 
148. 

Meckel's cartilage, Frog, 212. 

Medul'la (L. pith), Rockweed, 289; 
oblongata, Frog, 248. 

Med'ullary rays, Stem, 353. 

Medullated nerve-fibres, Frog, 260. 

Medu'sa, pi. medusas {Gr. Medusa, a 
mythological being with serpent- 
entwined head), Hydroid, 94. 

Mer'istem ( Gr. divide), actively divid- 
ing; cell-tissue. Fern, 329. 



Mes'entery (Gr. middle intestine), 
Frog, 230; Starfish, 107. 

Mes'oderm (Gr. middle skin), Star- 
fish, 120. 

Mes'ophyll ( Gr. middle, a leaf), Fern, 
331 ; Leaves, 366. 

Met'ameres (Gr. after, a part), serial- 
ly homologous divisions of an or- 
ganism, Lobster, 140. 

Met'azoa (Gr. after, an animal), ani- 
mals whose bodies consist of cells 
which differ in structure and func- 
tion, 21. 

Micronu'cleus ( Gr. small, L. a kernel), 
Slipper Animalcule, 13. 

Mi'cropyle (Gr. small orifice), Flow- 
ers, 376 ; Seeds, 337. 

Microscope, Use of, xxi. 

Mollusc Shells, 189. 

Mould, 297; asci, 300; ascospores, 
300 ; conidia, 299 ; conidiophore, 
298, 299 ; germination of conidia, 
300; hyphae, 298; mycelium, 298 ; 
sporocarp, 299 ; sterigma, 299. 

Multicellular Animals, isolated 
cells from, 21. See Metazoa. 

Multicellular Plants, isolated cells 
from, 46. 

Muscular tissue, Frog, 259 ; Lobster, 
156. 

Mushroom, 301; annulus, 302, 303; 
basidia, 306 ; basidiospore, 306 ; 
gills, 302; lamellae, 302; paraphy- 
ses, 306 ; pileus, 302 ; sterigmata, 
306; stipe, 302, 303. 

Myce'lium (Gr. a fungus, an excres- 
cence), Mould, 298 ; Mushroom, 303. 

My'elon (Gr. marrow), Frog, 246. 

My'ophan (Gr. muscle, appear), layer, 
Bell Animalcule, 19. 

N 

Nectar, Flowers, 372. 

Nem'atocyst (Gr. thread bag), Hydra, 
87 ; Hydroid, 93. 

Nephrid'ium, pi. nephridia (Gr. kid- 
ney), Earthworm, 133. 



INDEX AND GLOSSARY 



419 



Nervous properties, Hydra, 85 ; Lob- 
ster, 169 ; Slipper Animalcule, 16 ; 
Starfish, 113. 

Nervous system, Earthworm, 132 ; 
Frog, 245; Lobster, 164; Locust, 
184; Mussel, 200;. Starfish, 111. 

Nervous tissue, Frog, 260. 

Neural arch, Frog, 210. 

Nodes, Fern, 322 ; Stonewort, 275. 

Notes, xx. 

Nucel'lus (L. a little nut), Flowers, 
376. 

Nu'cleus, pi. nuclei (L. a kernel), 
Amoeba, 8; cell, 30; Frog, 259, 
260 ; Paramecium,, 13 ; Water Silk, 
55. 

Nutrition, Amoeba, 9 ; Frog, 261 ; Hy- 
dra, 85 ; Slipper Animalcule, 15 ; 
Starfish, 113. 



Olfactory capsule, Frog, 212; nerve, 
Frog, 247, 254. 

Oogo'nium, pi. oogonia (Gr. egg gen- 
eration), the ovary of lower plants, 
Green Felt, 270. 

0'6sphere(6V. egg, a sphere), the ovum 
of plants, Fern, 335 ; Green Felt, 
271 ; Rockweed, 294 ; Stonewort, 
280. 

O'ospore (Gr. egg, seed), Green Felt, 
271 ; Stonewort, 281. 

Organ of Bojanus, Mussel, 201. 

Organs of special sense, Lobster, 151. 

Os'culum, pi. oscula (L. a little 
mouth), Sponge, 76. 

Osmo'sis (Gr. pushing), the diffusion 
of fluids through membranes, Seeds, 
347. 

Os'sicles (Gr. little bones), Starfish, 
105 ; gastric, Lobster, 160. 

Os'tiole (L. a little opening), Rock- 
weed, 288, 292. 

O'tocyst (Gr. ear sac), Mussel, 201. 

Ovary, Earthworm, 134; Flowers, 
374 ; Frog, 235 ; Hydra, 88 ; Lob- 
ster, 164 ; Locust, 183. 



Ovipos'itor (L. egg, lay), Locust, 179. 

Ovule, Flowers, 374. 

O'vum, pi. ova (Gr. an egg), Hydra, 

89 ; Starfish, 116 ; segmentation of, 

Starfish, 118. 



Pal'lium (L. a mantle), Mussel, 194. 

Pal'pus, pi. palpi (L. feel), Lobster, 
148; Locust, 175, 176; Mussel, 
197. 

Pancreas, Earthworm, 130; Frog, 
231 ; Starfish, 107. 

Paramecium (Gr. of longish shape), 
10. See Slipper Animalcule. 

Paranucleus (Gr. beside, L. a ker- 
nel), Slipper Animalcule, 13. 

Paraph'ysis, pi. paraphyses (Gr. be- 
side, grow), Liverwort, 316; Mush- 
room, 306. 

Paren'chyma {Gr. the spongy tissue 
of the lungs), Fern, 330; Rock- 
weed, 289 ; Stems, 352. 

Pectoral girdle, Frog, 209. 

Pedicella'ria, pi. pedicellariee (L. a 
little foot), Starfish, 104. 

Pelvic girdle, Frog, 209. 

Penicil'lium (L. a painter's brush), 
297 ; spores of, 46. See Mould. 

Pericardial sinus, Lobster, 156. 

Pericardium (Gr. around heart), Frog, 
237; Mussel, 199; Starfish, 110." 

Perickon'drium (Gr. around carti- 
lage), Frog, 259. 

Peripheral nervous system, Frog, 251. 

Per'isarc (Gr. around flesh), Hydroid, 
92. 

Peristome (Gr. around mouth), Bell 
Animalcule, 19; Pond Snail, 193 ; 
Starfish, 103. 

Pes (L. foot), Frog, 208. 

Phlo'em (Gr. bark), Fern, 330. 

Phyl'lotaxy (Gr. leaf, order), Leaves, 
363. 

Pi'a ma'ter (L. gentle mother), Frog, 
246. 

Pigment cells, Frog, 258. 



420 



INDEX AND GLOSSARY 



Pil'eus (Gr. a felt cap), Mushroom, 
302, 305. 

Pin'na, pi. pinnae, dim. pinnule (L. a 
wing), Fern, 321, 331. 

Pistil, Flowers, 374. 

Plant Cell, Morphology and Physiol- 
ogy, 28. 

Plants, Unicellular, 28 ; Multicel- 
lular, 46. 

Pleurobran'chia, pi. pleurobranchise 

. ( Gr. the side, gills), Lobster, 150. 

Podobran'chia, pi. podobranchiae (Gr. 
foot, gills), Lobster, 150. 

Pollen Grains, 48 ; germination of, 50. 

Pollen-sacs, Flowers, 373. 

Pond Scum, 51. See Water Silk. 

Pond Snail, 192. 

Primordial utricle, Green Felt, 269; 
Water Silk, 55. 

Proteids, Seeds, 346. 

Pro'teus ( Gr. a mythological sea-god 
who could assume different shapes), 
Animalcule, 6; physiology, 8; 
structure, 7. 

Prothallium {L. before thallus), Fern, 
333. 

Protococ'cus (Gr. first berry), 39. 
See Green Slime. 

Pro'toplasm (Gr. first moulded), 5; 
Starfish egg, 117; Yeast, 30. 

Protozo'a (Gr. first animals), 3. 

Pseudopo'dium, pi. pseudopodia (Gr. 
false foot), Proteus Animalcule, 7. 

Pte'ris (Gr. a feather), 320. See 
Fern. 

Pylo'rus {Gr. a gate), Frog, 231. 

Pyre'noids {Gr. the stone of a fruit, 
' form), Water Silk, 55. 



R 

Ra'chis {Gr. a rib of a leaf), Fern, 

321, 329. . 
Ra'na {L. a frog), 203. See Frog. 
Receptacle, Flowers, 371. 
Regeneration of lost portions of body, 

Starfish, 115. 



Reproduction, Amoeba, 10 ; Slipper 
Animalcule, 17; Starfish, 115; 
Yeast, 38. 

Reproductive organs, Starfish, 108 ; 
Stonewort, 275 ; system, Earth- 
worm, 133 ; Lobster, 163 ; Starfish, 
108. 

Respiration, Seedlings, 346. 

Respiratory system, Frog, 232; Star- 
fish, 111. 

Rhi'zoids, Fern, 334; Liverwort, 311, 
312 ; Stonewort, 281. 

Rhi'zome {Gr. root), Fern, 322. 

Rockweed, 285 ; antheridia, 294 ; 
apical cell, 291 ; conceptacles, 288, 
292 ; growing point, 289 ; oogonia, 
294; ostiole, 288, 292; thallus, 
287 ; trichomes, 292. 

Root, Fern, 329. 

Root-cap, Fern, 329 ; hairs, Fern, 322, 
328. 

Roots, 357. 

S 

Saccharomt'ces {L. sugar, Gr. fun- 
gus), 28. See Yeast. 

Salivary Cells, Metazoa, 21. 

Sarcolem'ma (Gr. flesh, skin), Frog, 
260. 

Scaphog'nathite {Gr. bowl, jaw), Lob- 
ster, 148. 

Seed-coat, 337. 

Seeds, 336. 

Segment. See Metamere. 

Segmental cell, Fern, 329 ; Stonewort, 
281 ; organs, Earthworm, 133. 

Segmentation of ovum, Starfish, 118. 

Sensation, Amoeba, 9; Hydra, 95. 

Sense capsules, Frog, 212. 

Se'ta, pi. setae (Z. a bristle), Earth- 
worm, 125. 

Sexual apertures, Earthworm, 126 ; 
generation, Fern, 333. 

Shells, Mollusc, 189. 

Shoulder-girdle, Frog, 209. 

Sinus, pericardial, Lobster, 156; ve- 
nosus, Frog, 238. 

Siphons, Mussel, 195. 



INDEX AND GLOSSARY 



421 



Skeleton, Frog, 209 ; Toilet sponge, 
65. 

Skull, Frog, 211. 

Slipper Animalcule, 10 ; automati- 
city, 16; conjugation, 17; co-or- 
dination, 16 ; fission, 17 ; irritabil- 
ity, 16; movements, 14; structure, 
12. 

So'mite (Gr. body), Earthworm, 124. 
See Metamere. 

So'rus, pi. sori (Gr. a heap), Fern, 
322. 

Spermathe'ca, pi. spermathecae (Gr. 
seed case), Earthworm, 127, 134. 

Spic'ules (L. a little spike), Grantia, 
77; Spongilla, 71. 

Spinal cord, Frog, 250; nerves, Frog, 
250, 251. 

Spir'acle (L. a breathing-hole), Locust, 
179. 

Spirogt'ra ( Gr. spire, circle), 51. See 
Water Silk. 

Spleen, Frog, 232. 

Sponges, 65. 

Spongil'la (L. a little sponge), 68. 
See Fresh-water Sponge. 

Sporan'gium, pi. sporangia (Gr. seed 
vessel), Fern, 322, 332. 

Spores, Fern, 322 ; Fungi, 46 ; Liver- 
wort, 318, 333; Penicillium, 46. 

Spo'rocarp (Gr. seed, fruit), Mould, 
299. 

Sporogo'nium, pi. sporogonia (Gr. 
seed generation), Liverwort, 318. 

Stamens, Flowers, 373. 

Starch formation, Water Silk, 58 ; 
grains, Water Silk, 55 ; microscopic 
examination of, Seeds, 341. 

Starfish, 97; circulatory system, 107; 
co-ordination, 114; digestive sys- 
tem, 107; direction cells, 117; fer- 
tilization, 118; heart, 110 5 move- 
ments, 112; nervous system, 111; 
nutrition, 113; ovum, 116; polar 
globules, 117; regeneration of lost 
portions of body, 115; reproduc- 
tion, 115; reproductive system, 108 ; 



respiratory system, 111; segmenta- 
tion cavity, 119; sight, 114; struct- 
ure of sexual cells, 116; touch, 113; 
water vascular system, 109. 

Stems, Flowering Plant, 348. 

Sterig'ma, pi. sterigmata (Gr. a sup- 
port), Mould, 299 ; Mushroom, 306. 

Sternum ( Gr. the breast-bone), Frog, 
216; Lobster, 141. 

Stig'ma (Gr. a pointed instrument), 
Flowers, 374. 

Stigmata, Locust, 179. 

Stipe (L. a stalk), Mushroom, 302, 
304. 

Sto'ma, pi. stomata (Gr. mouth), 
Fern, 332; Liverwort, 311, 313. 

Stonewort, 273 ; apical cell, 281 ; 
flagella, 280 ; movements of proto- 
plasm, 283 ; reproductive organs, 
275 ; rhizoids, 281. 

Style, Flowers, 373. 

Swimmerets, Lobster, 141. 

Sympathetic nervous system, Frog, 
253. 

T 

Teeth, gastric, Lobster, 161 ; vomer- 
ine, Frog, 215. 

Tel'son (Gr. end), Lobster, 144. 

Ten'tacle (Z. a feeler), Hydra, 83; 
aboral, Starfish, 103. 

Testa (L. a shell), Seeds, 337. 

Testis, pi. testes, Frog, 261. 

Tests, albumen, Seeds, 340 ; cellulose, 
Green Slime, 43 ; grape sugar, 
Seeds, 339; starch, Seeds, 338. 

Thalamenceph'alon, Frog, 247. 

Thal'amus, pi. thalami (Gr. an inner 
chamber). 

Thaflus (Gr. a young shoot), Liver- 
wort, 309 ; Rockweed, 287. 

Tho'rax (Gr. a breastplate), Locust, 

. 176. 

Toilet Sponge, 65. 

Trache'a, pi. tracheae (Gr. the wind- 
pipe), Locust, 181. 

Trache'id, Fern, 327, 330. 

Transpiration, Leaves, 367. 



422 



INDEX AND GLOSSARY 



Trich'ocyst (Gr. hair sac), Slipper 
Animalcule, 13. 

Tri'chome (Gr. a growth of hair), 
Fern, 329 ; Rockweed, 292. 

Turgescence, Seeds, 342. 

Twining, Stems, 356. 

Typh'losole (Gr. blind tube), Earth- 
worm, 130; Mussel, 199. 

U 

Um'bo (L. a knob), Mussel, 191. 

Unicellular Animals, 3 ; Plants, 28. 

Unio (L. one), 189. See Fresh-water 
Mussel. 

Urino-genital system, Frog, 234. 

U'tricle (L. a little leathern bag), pri- 
mordial, Water Silk, 55. 



Vacuole, Water Silk, 56; Yeast, 30; 

contractile, Proteus Animalcule, 8 ; 

Slipper Animalcule, 12. 
Vauche'ria (L. from Vaucher, a Swiss 

student of fresh-water algae), 26*7. 

See Green Felt. 
Veins, Fern, 331 ; Frog, 238. 
Ve'na ca'va, pi. venae cavse (L. vein, 

hollow), Frog, 238. 
Venation, Leaves, 364. 
Ventral ganglia, Earthworm, 132; 

nerve-cord, Earthworm, 132. 
Ventricle of heart, Frog, 237, 244 ; 

Lobster, 157 ; Mussel, 199. 
Ventricles of brain, Frog, 248, 249. 
Vernation, Buds, 361. 
Ver'tebra, pi. vertebrae (L. to turn 

about), Frog, 210. 
Vocal cords, Frog, 233 ; sac, Frog, 

229, 233. 



Vomerine teeth, Frog, 227. 
Vorticel'la (L. a little vortex), 18. 
See Bell Animalcule. 

W 

Water vascular system, Starfish, 109. 

Water Silk, 51 ; assimilation, 58 ; 
cell formation, 60; formation of 
starch, 58 ; structure, 55 ; zygo- 
spores, 57. 

Wood, Fern, 330; Stems, 351; pa- 
renchyma, Fern, 331. 

X 

Xy'lem (Gr. wood), Fern, 330; Stem, 
352. 

Y 

Yeast, 28; budding, 38; chemical 
reaction of fluid, 36 ; effect of fil- 
tered, 37; effect of food supply 
upon growth, 31 ; effect of light 
upon growth, 33 ; effect of tem- 
perature upon growth, 33 ; endoge- 
nous spore formation, 38; forma- 
tion of alcohol, 36 ; gemmation, 38 ; 
nature of gas given off by growing, 
34 ; nucleus, 30 ; temperature dur- 
ing growth, 36. 



Zoogonid'ium, pi. zobgonidia (Gr. 

animal, a small seed), Green Felt, 

271. 
Zo'oid (Gr. animal, form), Hydroid, 

91. 
Zo'ospore (Gr. animal, seed), Green 

Felt, 271 ; Green Slime, 44. 
Zygospore (Gr. yoke, seed), Water 

Silk, 57. 



THE END 



ORTON'S COMPARATIVE ZOOLOGY. 



COMPARATIVE ZOOLOGY, Structural and Systematic. For 
Use in Schools and Colleges. By James Orton, Ph.D., 
Professor of Natural History in Vassar College ; Correspond- 
ing Member of the Academy of Natural Sciences, Philadel- 
phia, and of the Lyceum of Natural History, New York; 
Author of " The Andes and the Amazon," etc. 

The distinctive character of this work consists in the treat- 
ment of the whole Animal Kingdom as a unit; in the compara- 
tive study of the development and variations of organs and their 
functions, from the simplest to the most complex state j in with- 
holding Systematic Zoology until the student has mastered those 
structural affinities upon which true classification is founded ; 
and in being fitted for high -schools and mixed schools by its 
language and illustrations, yet going far enough to constitute a 
complete grammar of the science for the undergraduate course 
of any college. It is designed solely as a manual for instruc- 
tion. It is not a work of reference, not a treatise. So far as a 
book is encyclopaedic, it is unfit for a text-book. This is pre- 
pared on the principle of " just enough, and no more." It aims 
to present clearly, and in a somewhat new form, the established 
facts and principles of Zoology. All theoretical and debatable 
points, and every fact or statement, however valuable, which are 
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